The 6th international conference on particle physics and astrophysics

The last undiscovered particle of the Standard Model, the Higgs boson, was observed in 2012 by the ATLAS and CMS Collaborations at the Large Hadron Collider at CERN. Since that time the cross sections of main five production mechanisms at $\sqrt{s}$ = 7, 8 and 13 TeV pp collisions were measured as well as branching ratios of five decay channels, a mass and a width. It was also established that a spin and a parity of the Higgs boson are 0+. In addition, differential cross sections on many kinematic variables were measured. No deviations from the Standard Model predictions were observed. The precision of the measurements at the LHC is permanently improving with analyzing new data. This talk summarizes experimental situation with the Higgs boson after ten years of its discovery mostly based on full $\sqrt{s}$ = 7, 8 and 13 TeV datasets accumulated by the ATLAS and CMS detectors during Run1 and Run2 of the LHC.

Summary of recent Standard Model measurements performed by ATLAS and CMS experiments at LHC (CERN).

Review of recent heavy flavour results obtained by the ATLAS and CMS collaborations
will be presented. The results will be compared with those from other experiments
and with theoretical predictions. Prospects for further studies
will also be outlined

The development of the GAMMA-400 gamma-ray telescope for cosmophysical research continues under the Russian Federal Space Program. The GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory, which will be operating in a highly elliptic orbit during 7 years to provide new data on gamma-ray emission and cosmic-ray electron + positron fluxes mainly from the Galactic plane, Galactic Center, and the Sun. The main mode of observations will be the continuous point-source mode with duration of up to ~100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emission up to several TeV and cosmic-ray electrons + positrons up to 20 TeV. GAMMA-400 will have the never-achieved angular resolution, the high energy and time resolutions, as well as very good separation efficiency of gamma rays from cosmic-ray background and electrons + positrons from protons. The distinctive feature of GAMMA-400 is the wonderful angular resolution for energies >30 GeV (~0.01° for Eγ = 100 GeV) that exceeds resolutions of the space-based and ground-based gamma-ray telescopes by a factor of 5-10. GAMMA-400 studies can reveal gamma-ray emission from annihilation or decay of dark matter particles, identify many unassociated discrete sources, explore the structure of extended sources, improve the data on cosmic-ray electron + positron spectra for energies >30 GeV.

We first analize the effects of an electric field on the effective potential in a self interacting scalar theory, finding electric anticatalysis in the weak field region, i.e. a critical temperature that diminishes as function of the intensity of the electric field. The physical situation corresponds to collision between heavy and a light nuclei, for example Au-Cu collision, where due to the imbalance in the number of protons in the initial state, a strong electric field in the plane of the collission appears. In a second step we consider the effects of an alectric and a magnetic field. perpendicular to each other again in the scenario of a self interacting scalar theory. In this case, we have inverse magnetic-electric catalysis (IMEC), where both fields cooperate in the diminishing behavior of the critical temperature. We present also some results concerning the mass evolution.

Cosmic rays are highly energetic particles emitted from different galactic and extragalactic sources.These primary particles propagate through interstellar space until they reach the Earth's atmosphere. The number of particles detected on the surface of Earth is not the same depending on the direction viewed in the sky, it varies with the zenith angle. In this work, we calculate the angular distribution of cosmic rays nuclei taking into account the influence of certain environmental factors such as the altitude and Earth's magnetic field. The results were obtained using the most recent version of the EXPACS code and the latest experimental data.

An analytical approximation of the local non-equilibrium distribution function of neutrinos which propagate spherically symmetric in the core-collapse supernova is obtained. In general, the fitting formula depends on four parameters but it can be simplified when the outer part of supernova is considered only. In this part, two fitting parameters are practically independent on the distance from the supernova center while the other one parameter is determined by the supernova luminosity. The check of this approximation is based on the data on the one-dimensional simulations of the neutrino propagation, being self-consistent with the supernova explosion hydrodynamics ( Prometheus-Vertex code).

Astrophysical radio experiments in Antarctica and Greenland are designed to search for neutrinos with ultra high energies. The method of their detection is based on the search for Askaryan radio pulses emitted by showers from the interaction of neutrinos in ice. For these experiments, it is important to know what pulsed radio noise may be present in order to distinguish them from rare neutrino events. And it is also important to understand what contributes to the constant radio background, because the energy threshold and the effective volume of the detectors depend on the noise level. Also a detailed study of the radio noise and its nature may allow checking the calibration of the system.
The paper presents the results of studying the sources of radio noise in experiments at the South Pole. The influence of anthropogenic activity and periods of strong storms was determined using the data of the AURA experiment.
The contribution of galactic noise, thermal noise from ice, and electronic noise to the radio background level is analyzed using the data of the RNO-G experiment in Greenland.

The upcoming LHCb calorimetry upgrade, aimed to allow LHCb detectors to operate with higher luminosity, implies significant hardware modifications to the present ECAL. These changes include replacement of the current shashlik-type modules with spaghetti-type for the inner part, upgrade of the shashlik modules to improve time resolution and possible removal/modification of the HCAL (Hadron Calorimeter). Such changes require detailed studies including the test beam campaign with electron and hadron beams of different energies.
This talk presents the results of the hadron beam particle composition analysis performed at H8 testbeam line in August 2021. The analysis is based on the data recorded with a standard single-cell LHCb ECAL module, threshold Cherenkov detector and tracking system based on three DWC (delay-wire chamber) stations.

V. O. Nesterenko$^{1,2}$, M.A. Mardyban$^{1,2}$, P.-G. Reinhard$^3$, A. Repko$^4$

$^1$Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow Region 141980, Russia

$^2$ Dubna State University, Dubna, Moscow Region 141982, Russia

$^3$ Institut für Theoretische Physik II, Universität Erlangen, D-91058, Erlangen, Germany

$^4$Institute of Physics, Slovak Academy of Sciences, 84511 Bratislava, Slovakia
E-mail: mmardyban@mail.ru

We suggest the self-consistent description of the ground-state moment of inertia (MI) in highly prolate light nuclei $^{24}$Mg and $^{20}$Ne (with experimental equilibrium axial quadrupole deformations $\beta_2$=0.605 and 0.72, respectively [1]). These nuclei provide an interesting opportunity to explore dependence of MI on the pairing, ground-state correlations and nuclear shape at extreme deformations. The calculations are performed with Skyrme forces SVbas, SkM*, and Sly6 for deformation range 0.1 < $\beta_2$ < 1.6. Three approaches are applied [2]: Inglis-Belyaev (within Hartree-Fock-Bogoliubov method), QRPA Thouless-Valatin (within Quasiparticle Random-Phase Approximation method [3]) and ATDHF (Adiabatic Time-Dependent Hartree Fock method). For Inglis-Belyaev and ATDHF calculations, the code SKYAX [4] was used. All three approaches show that, near the equilibrium deformation, the pairing in $^{24}$Mg and $^{20}$Ne vanishes and we get the maximum of MI. With further grow of the deformation above the equilibrium values, we see decrease of MI. Such behavior of MI is explained by rearrangement of single-particle levels with deformation. The analysis reveals main two-quasiparticle contributions responsible for the behavior of MI in different regimes.

1. Database http://www.nndc.bl.gov

2. P.Ring and P.Schuck, TheNuclearMany-BodyProblem (Springer-Verlag,Berlin,1980)

3. A. Repko, J. Kvasil and V.O. Nesterenko, Phys. Rev. C 99, 044307 (2019).

4. P.-G. Reinhard, B. Schuetrumpf, and J. A. Maruhn, Comput. Phys. Commun. 258, 107603 (2021).

One of the features of general relativity is the possible existence of space-time with a nontrivial topological and casual global structure . The real three-dimensional space might in principle be multiply connected and there might exist wormholes in it. It was shown that a stable wormhole ( if only exist ) can be transformed into a time machine. If we take into account quantum field fluctuations in given space with wormhole , we find amplification of fluctuations in approaching to Cauchy horizon. Renormalized stress-energy tensor of a quantum field diverge at the Cauchy horizon. In particular quantum field energy become infinite. Usually this fact is interpreted as impossibility to create time machine (chronology protection). This result was obtained in classical consideration of given wormhole's throats motion and quantum field effects in given geometry.
In present paper we use quantum mechanics for calculation of wormhole's throats motion . This approach gives the possibility of time-machine creation of the order of 1. This process is very similar to Quantum tunnelling in standard quantum mechanic.

We discuss the model of the primordial black holes formation at the reheating stage. These small massive black holes appear due to specific properties of the compact extra dimensions. The latter gives rise the low energy model containing the effective scalar field potential capable for the domain walls production. Formed during inflation, these walls are quite dense so they collapse soon after inflation ends. The discussion is performed within the scope of multidimensional $f(R)$-gravity.

The PAMELA electromagnetic calorimeter consists of 44 single-sided silicon sensor planes interleaved with 22 plates of tungsten absorber. It provides a comprehensive information about spatial development of hadronic showers, and about deposited energy amount.

In this work, Monte Carlo simulations (based on Geant4) performed using different available models, including Fritiof (FTF) and Quark Gluon String (QGS) models of high energy hadron–nucleus interactions with Li\~ege (INCL) and Bertini (BERT) intranuclear cascade models. We compared various hadronic shower parameters of simulated data with the data obtained during PAMELA experiment. These parameters describe energy release in the calorimeter, longitudal profile, position of the shower maximum etc.

ALICE has installed four new detectors during a three-year upgrade preceding the just-started LHC Run 3. One of them is Fast Interaction Trigger (FIT). It consists of three subdetectors: FT0, FV0 and FDD. The uniformity of subdetectors’ front-end electronics (FEE), HV system and infrastructure allowed us to develop a unified approach to control its parameters. Here we describe the implementation of the FIT detector control facilities represented by two types of software. The first one, based on the SCADA system WinCC OA, provides HV control and detector infrastructure integration into the ALICE Detector Control System (DCS). The second is an application that binds FEE and the WinCC OA and provides an independent graphical user interface for electronics tuning. The experience gained during the first year of FIT operation gives us the understanding to implement further improvements to the control system.

The search for neutrinoless double beta decay remains today one of the most important areas in particle and nuclear physics. Germanium detectors are an excellent technology for this search because of state-of-the-art energy resolution, but dead layers in germanium crystal could potentially harm the energy resolution.
In this work, we used machine learning methods to study the dead layer in enriched germanium crystals. 1000 sets of events were simulated with various combinations of dead layer parameters. A fully connected neural network was used to determine these parameters from the energy spectra of a gamma calibration source Ba 133. As a result of training, this neural network determines the thickness of the dead layer with an accuracy about 0.01 mm and it's fraction with an accuracy about 1%.

The angular distributions for the 11.28 (7/2+), 11.82 (9/2-), and 13.79 (7/2-) MeV states were obtained and analyzed from the scattering of light particles by the 9Be nucleus.[1,2]. The MDM method was used to estimate the radii [3]. The resulting diffraction radius of the 11.82 MeV state turned out to be equal to the radius of the ground state. This indicates that the root-mean-square radius of this state is ordinary. For the 11.28 MeV and 13.79 MeV states, the diffraction radii turned out to be increased, which indicates increased root-mean-square radii for these states.
On the basis of the obtained radii and certain spin-parity values (rule J(J+1) [4]) of the states 11.82, 11.28, and 13.79, it was possible to assign them to the first, second, and third bands of the 9Be nucleus, respectively.

[1] A.S. Demyanova et al., EPJ Web of Conferences 66 02026 (2014)

[2] A.S. Demyanova et al., JETP Lett. 104 (5) 289-292 (2016)

[3] A.N. Danilov et al., Phys. Rev. C 80, 054603 (2009)

[4] V.I. Starastsin et al., EPJ A 57, 334 (2021)

The possible entropy production scenarios in the early
universe are revisited. From the particle physics viewpoint we consider
electroweak phase transition (EWPT) in the standard model (SM) and
beyond standard model (BSM) scenarios like 2 Higgs doublet model (2HDM)
as a source of entropy influx into the primordial plasma. First order
phase transition in the case of 2HDM is realised. From a cosmological
viewpoint the evaporation of mini primordial black holes (PBH) in their
matter dominated (MD) stage in the early Universe is considered for the
same. The production of entropy and in turn the dilution of preexisting
baryon asymmetry and the dark matter density are considered in details
as well as possible production of entropy as a result of first order
phase transition is discussed qualitatively.

The current level of development of experimental facilities makes it possible to conduct studies of both relatively long-lived nuclei forming the valley of stability and exotic nuclei lying outside this region. The production of exotic nuclei is a rather difficult task, one of the solutions of which was the using radioactive isotopes beams accelerated to energies above the Coulomb interaction barrier in the experiments.

To obtain beams of radioactive isotopes, the In-Flight method, in which radioactive isotopes are obtained in fragmentation reactions is currently widely used. Beams of radioactive isotopes are formed using fragment separators. The efficiency of the fragment separator depends on the relative yield and momentum distributions of radioactive isotopes. In this regard, predictive calculations of these characteristics are of particular importance. Despite the fact that the yields and momentum distributions of radioactive isotopes in fragmentation reactions have become the subject of systematic studies for high and medium energies (more than 100 MeV per nucleon), In-Flight complexes for the production of radioactive beams work not only at high, but also at low energies. However, there are no detailed studies of fragmentation reactions for low energies (from 10 MeV per nucleon). Thus, it is important to investigate both the fragmentation mechanism itself and its features at low energies, and it is also important to develop a method for evaluating various characteristics of fragmentation products.

In this work the primary results of estimating the longitudinal momentum distributions of fragmentation reaction products in the energy range from 10 to 50 MeV/nucleon are presented.

One of the most actual questions of particle physics and cosmology today is the nature of Dark Matter. Experiments on the direct search for dark matter particles are aimed to direct detection of Weakly Interaction Massive Particles (WIMP) or obtaining constraints on their space of mass parameters and spin-independent interaction cross sections.

For WIMPs (from a few GeV/c$^2$ to TeV/c$^2$) searches, the best results are shown by the noble liquid time projection chambers (TPCs). The signal in the LAr TPC is observed both from excitation, which results in a direct scintillation, and from ionization of argon. Electrons that have not recombined after ionization are drifted in the applied electric field towards the liquid surface, and after extracted into the gas phase. In the so-called gas pocket, electrons, further accelerated by a stronger electric field, excite the gas atoms and produce a secondary scintillation via electroluminescence. Interaction parameters and coordinates of the events inside TPC are reconstructed using both primary scintillation in liquid argon and electroluminescence scintillation in the gas pocket.

In this study simulations of electron drift and electron cloud diffusion were performed for the TPC of the ReD experiment, which aimed at nuclear recoil studies in a neutron beam at the INFN Laboratori Nazionali del Sud in Catania. The results of the evaluation of the influence of the electric field nonuniformity on the charge accumulation on the detector chamber walls and the error of the reconstructed coordinates of events are presented in the talk.

Neutrinoless double beta decay search is one of the most significant tasks in nuclear and elementary particle physics. The detection of this process will provide information on such fundamental issues as the absolute neutrino mass scale, the type of neutrino hierarchy (normal or inverse), and violation of CP parity in the lepton sector. One of the supposed options is a process involving the emission of majoron  presumable candidate for dark matter components. Discovery of this process will immediately lead to the discovery of a new elementary particle – the majoron. All this, in turn, will lead to the important consequences in physics and astrophysics. The sensitivity of modern experiments to the half-life of nuclei has been brought to ~ 1025–1026 years [A.S. Barabash, Int. J. Mod. Phys. A, 33 (2018) 1843001].
One of the most promising future experiments is the CUPID-Mo [E. Armengaud, E. Phys. J. C, 80(1) (2020) 44]. The CUPID Mo experiment is based on low-temperature scintillating bolometers with Li2100MoO4 crystals as detecting elements. Li2100MoO4 was chosen because of high molybdenum ratio and possibility of enrichment with molybdenum-100 (100Mo) isotope.
Thus, developing techniques for obtaining large Li2MoO4 crystals of high optical quality becomes an important task in crystal growth field. The extreme rarity of double beta decay imposes strict requirements on crystal scintillators. In addition to the general requirements for scintillators - high optical quality, light output, energy resolution, the material must also contain a minimum amount of impurities and have an ultra-low radiation background.
Above listed requirements make the low-thermal-gradient Czochralski technique (LTG Cz), developed at NIIC SB RAS, a unique technology for growing Li2MoO4 crystals. The method has significant structural differences from the conventional Czochralski technique, due to which the temperature gradients inside the heater are reduced by two orders of magnitude, to values less than 1 deg/cm. Due to this, the processes of volatilization of the melt components are suppressed, the loss of expensive isotopically enriched molybdenum-100 during growth is prevented, the amount of thermoelastic stresses and defects in the growing crystal is reduced.
In presented work, an approach for growing Li2MoO4 crystals of high optical quality was developed. The approach implied conversion of growth parameters to establish normal growth mechanism instead of layered one traditionally implemented in LTG Cz. Optimal growth parameters were determined based on morphology and defects concentration in grown crystals. Reproducible growth of 120 mm long Li2MoO4 crystals was achieved, and 50 uniform crystals were obtained.

The study of the thermonuclear reaction rates of neutrino production in the primordial hot region is essential for understanding primordial nucleosynthesis in regions formed by primordial density inhomogeneities. We considered the thermonuclear reaction rates due to effects of electron-positron annihilation, reactions of weak proton-neutron transitions, and the production of light nuclides during the early stages of the universe. It is shown that the major neutrino production channel is electron-positron annihilation at higher temperatures, which is dominant in comparison to other thermonuclear reaction rates. However, the reaction rates slow down as the region cools down due to threshold effects, a drop in neutron concentrations, and electron-positron annihilation. Furthermore, a region with an abnormal chemical composition formed.

The aim of the present work was to measure the yield ratios of the 85m,gSr produced in the natSr(γ,xn) reactions with bremsstrahlung end-point energy 55 MeV. The study examined the possibility of producing 85Sr isotope in photonuclear reactions on a natural mixture of strontium isotopes. The radionuclide 85Sr has decay parameters such as half-life and photon energies suitable for the nuclear medical applications. So far, it has been widely used in the scanning of suspected bone disease. Usually, the 85Sr is produced through the 85Rb(p,n) nuclear reaction. The investigated multiparticle photonuclear reactions natSr(γ,xn)85m,gSr can also be considered as part of a complementary method for the production of the 85Sr medical isotope. The yields of the target nuclide 85m,gSr were measured as a result of natSr(γ, xn) reactions. The isomeric ratio is obtained for 85m,gSr. The value found for this isomeric ratio is compared with the results of other studies and with the results of calculations based on TALYS-1.96.

We obtain kink solutions for a family of field-theoretic models with polynomial self-interaction of a real scalar field. These solutions have power-law asymptotics, and hence can be used for modelling of the so-called thick domain walls (among other applications). We also study various properties of the obtained solutions.

At the Baksan Neutrino Observatory deployed in the North Caucasus mountains, it is proposed to develop, at a depth corresponding to about 4700 mwe, a large-volume neutrino detector based on a liquid scintillator with a target mass of 10 kt. The main physics goals of the detector are low-energy neutrino physics, astrophysics and geophysics. The highest possible light yield is crucial for such detectors. To improve light yield and energy resolution in large-volume neutrino detectors, light concentrators are often mounted on photomultiplier tubes to increase the detection efficiency of optical photons from scintillation or Cherenkov light induced by charged particles. We present the results of recent R&D work aimed to develop light concentrators for the Baksan large-volume liquid scintillator neutrino detector.

Machine Learning methods are proposed to be used for particle identification (PID) in more and more experiments at high energy physics nowadays. Particle identification plays an important role in high-energy physics analysis therefore determines the success of performing an experiment. This determines the importance of using machine learning to improve particle identification in the regions where conventional methods fail to provide good identification. This report gives first tests of machine learning methods applications using gradient boosting on decision trees to particle identification problem in MPD experiment.

In addition to classical analytical data processing methods, machine learning methods are widely used for data analysis in elementary particle physics. Most often such techniques are used to identify a particular class of events (the classification problem) or to predict a certain event parameter (the regression problem). Here we present the result of using a machine learning model to solve the regression problem of event position reconstruction in the DEAP-3600 dark matter search detector. Several machine learning algorithms have been tested on Monte Carlo simulation data and compared with analytical models. The results suggest that this technique can be used in conjunction with the analytical models to improve the quality of the reconstruction.

The electroweak production of $Z(\nu\bar{\nu})\gamma$ in association with two jets is studied in a regime with a photon of high transverse momentum above 150 GeV using proton--proton collisions at centre-of-mass energy of 13 TeV at the Large Hadron Collider. The analysis uses a data sample with an integrated luminosity of 139 fb$^{-1}$ collected by the ATLAS detector during the 2015--2018 LHC data taking period.
This process is an important probe of the electroweak symmetry breaking mechanism in the Standard Model and is sensitive to quartic gauge boson couplings via vector-boson scattering. The fiducial $Z(\nu\bar{\nu})\gamma jj$ cross section for electroweak production is measured to be 0.77$^{+0.34}_{-0.30}$ fb and is consistent with the Standard Model prediction.
Evidence for the electroweak $Z(\nu\bar{\nu})\gamma jj$ production is found with an observed significance of 3.2$\sigma$ in the background-only hypothesis, compared with an expected significance of 3.7$\sigma$.
The combination of this result with the previously published ATLAS observation of electroweak $Z(\nu\bar{\nu})\gamma jj$ production yields in an observed (expected) signal significance of 6.3$\sigma$ (6.6$\sigma$). Limits on anomalous quartic gauge boson couplings are obtained in the framework of effective field theory with dimension-eight operators.

An excess of positrons in cosmic rays (CR) called positron anomaly was discovered more than decade ago and still stays an open-ended question in astrophysics. There is a big group of models involving annihilating or decaying Dark Matter (DM) purported to explain the anomaly. But they face an obstacle in the form of gamma-rays. Simple DM models tend to overproduce gamma-rays, leading to contradiction with isotropic gamma-ray background (IGRB). This work is dedicated to attempt to alleviate the contradiction by modifying the spatial distribution of DM. It’s obtained that such an approach allows improving anomaly data fit considerably.

Models of the origin of astrophysical neutrinos with energies from TeVs to PeVs are strongly
constrained by multimessenger observations and population studies. Recent results point to statis-
tically significant associations between these neutrinos and active galactic nuclei (AGN) selected
by their radio flux observed with very-long-baseline interferometry (VLBI). This suggests that the
neutrinos are produced in central parsecs of blazars, AGN with relativistic jets pointing to the
observer. However, conventional AGN models tend to explain only the highest-energy part of the
neutrino flux observationally associated with blazars. Here we discuss in detail how the neutrinos
can be produced in the part of an AGN giving the dominant contribution to the VLBI radio flux,
the radio core located close to the jet base. Physical conditions there differ both from the immediate
environment of the central black hole and from the plasma blobs moving along the jet. Required
neutrino fluxes, considerably smaller than those of photons, can be produced in interactions of
relativistic protons, accelerated closer to the black hole, with radiation in the core

To improve the sensitivity to CP violation, reduce systematic uncertainties, T2K launched an intensive upgrade program that includes the upgrade of the near neutrino detector ND280. A novel 3D highly granular scintillator detector, called SuperFGD, of a mass of about 2 tons will have the full polar angle coverage for charged particles produced in neutrino interaction, a low threshold for proton detection and a capability to measure neutrons using time-of-flight. It consists of about two million of small optically isolated polystyrene based plastic scintillator cubes with a 1 cm side. Each cube is read out in three orthogonal directions with wavelength shifting fibers inserted into three holes and coupled to compact photosensors, Micro Pixel Photon Counters (MPPC). The cubes for SuperFGD detector were made by injection molding, and the holes are drilled using a high-precision machine. The new technology for production of scintillation elements is to develop a press-form which makes cubes with 3 orthogonal holes. This will significantly improve the geometric parameters of the elements, such as the dimensions accuracy and the precision of the hole position, which is extremely important for assembly of a new SuperFGD type segmented detectors with a mass of a few tons. However, the use of such mold introduces a new challenge of coating the surface of the cubes by an optical reflector. The details of new technologies and test results of the first samples of scintillation elements will be presented.

The Noble Element Simulation Technique (NEST) is a C++ package with optional GEANT4 integration and a Python equivalent (nestpy) developed for liquid noble gases experiments. It is capable of accurate predictions of scintillation and ionization signal from different particles for a large range of drift fields in liquid xenon and argon and is widely used by leading dark matter and neutrino experiments. Using a combination of empirical and first principle methods, NEST models the intrinsic physics of noble detectors while maintaining a user-friendly format. Applicability, adaptability and future plans of NEST will be discussed.

We obtain estimates for the kink-antikink force of interaction. We consider the case of kinks with power-law asymptotics, which is used, in particular, to model thick domain walls. We use a method based on a special type of field approximation between a kink and an antikink.

The EGRET and Fermi LAT experiments have revealed a lot of unidentified gamma-ray sources. Moreover, a significant part of EGRET sources have not been confirmed by the Fermi LAT data. The possibility for the closest to Solar system unidentified gamma-ray sources to be moving in the selestial sphere during the time period between the EGRET and Fermi LAT experiments is considered. The nature of such gamma-sources might be associated with compact objects of new physics, such as clumps of dark matter or clusters of primordial black holes. We construct a distribution function of moving sources versus galactic coordinates and perform a statistical analysis to estimate whether the displacement effect is significant for the unidentified sources which have been found in the EGRET and Fermi LAT experiments.

The BM@N (Baryonic Matter at Nuclotron) is the first running experiment at the NICA accelerator complex and is aimed at studying the QCD diagram at high baryon densities. The forward detectors of the BM@N experiment are the forward hadron calorimeter, scintillation wall and quartz hodoscope. The forward detectors are used to determine the centrality and orientation of the reaction plane, and to study the charge distributions of spectator fragments formed in nucleus-nucleus interactions. The online real-time monitoring system recently developed for the forward detectors is discussed.

The DarkSide-20k (DS-20k) experiment seeks to directly detect dark matter in the form of weakly interacting massive particles (WIMPs). DS-20k is a two-phase liquid argon (LAr) Time Projection Chamber (TPC) with an active volume of 50 tonnes, which is built in the Outer Veto. The Outer Veto is approximately 650 tonnes of atmospheric argon (AAr) in a membrane cryostat, designed to veto cosmogenic neutron backgrounds in the TPC. The Outer Veto will tag cosmogenic neutron backgrounds based on the signal that muons or their associated showers may make in it.

The optical properties of the Outer Veto define its ultimate efficiency for tagging cosmogenic signals. To understand the response of the Outer Veto to muons and optimize its performance, the effects of various design considerations on the light yield and uniformity of the outer veto are explored.

Optical simulations were performed with a geant4-based framework.

The modeling was carried out for different options for the number of photosensors and their position. Cosmic muons were used in the simulation. Different options for the location of the flanges were considered. The light yield was calculated for each configuration.

As a result of studying the optical characteristics of the Outer Veto, it was found that light yield varies depending on several design parameters, including the number and location of photosensors and the choice of reflector.

At present, production, properties, and decays of heavy baryons are intensively studied both experimentally and theoretically. The $SU(3)$ flavor symmetry allows an existence of a large number of hidden charm pentaquark states which differ in their light quark content. Here, ratios of weak decay width of bottom baryons into a pentaquark and light meson are presented. The most interesting for experimental observation decays of bottom baryons are specified.

The method of induced activity was used to study photonuclear reactions on a natural mixture of selenium isotopes. This study measured the yields of the radionuclides 73(m+g)Se, 75Se, 79mSe, 81(m+g)Se, 71As, 72As, 74As, 76As, 77As, 78As, and 79As produced in natSe(γ, xnyp) multiparticle reactions with bremsstrahlung end-point energy of 55 MeV. The bremsstrahlung radiation was generated using the RM-55 electron accelerator at at the Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Russia, and the reaction yields were derived from the induced activities measured using off-line γ-ray spectrometry. The measurement of the production yields for the radionuclides produced in the photoproton reactions on natural selenium is the first of its kind. The experimentally obtained yields of photonuclear reactions are compared with the yields calculated using theoretical cross-sections of photonuclear reactions from CMPR and the TALYS program. On the whole, we can see a satisfactory agreement between the experimental yields and the theoretical calculations. The difference in values can be due to two main factors: TALYS uses default photoabsorption cross-sections, and also does not take into account the isospin splitting of the giant dipole resonance, which has a significant effect on the yields of photoproton reactions. There is a good agreement between the experimental data and the results of calculations by the CMPR method for both photoneutron and photoproton reactions.

Stellar cluster, observed in dwarf galaxy Eridanus II, provides strong constraint on abundance of massive compact halo objects (MACHOs) of mass $10 M_{\odot} \leq M\leq 10^6 M_{\odot}$, so they cannot be the main component of dark matter. MACHO dark matter should dynamically heat the cluster, driving it to larger sizes and higher velocity dispersions until it dissolves into galaxy.
Primordial black holes (PBH) are subject to this constraint. PBHs are now of special interest in connection to LIGO/Virgo results, early quasars observation, but historically first reason of very great interest to PBH is accounted for by dark matter (DM) problem. There have been plenty of works considering PBH as DM candidate, but, unfortunately, most of them just only put constraints overlapping each other on all relevant mass range. We consider cluster of PBHs of cluster mass within interval constrained from Eridanus.

Project of a compact muon hodoscope for muonography of various objects.

Tselinenko M. Yu.1, Kompaniets K. G1, Pasiuk N. A.1, Shutenko V.V.1, Yashin I. I.1

1NRNU MEPhI, Russia, Moscow, MYTselinenko@mephi.ru

Report Type: Poster.

At present, the method of muonography (by analogy with X-ray diffraction radiography) of the internal structure of various natural and artificial objects using the natural flux of cosmic ray muons has become widespread.

To implement the method, in the Experimental complex NEVOD (NRNU MEPhI) R&D research to develop a compact and precise muon hodoscope (CMH) started in the SEC NEVOD (NRNU MEPhI). The design of the horoscope is a multichannel detecting system consisting of four coordinate planes (CP) with an area of 1 m2. Each CP includes two detecting layers with orthogonal orientation of scintillation strips. Each layer is formed from an assembly of 96 scintillation strips with light collection by WLS fibers (fibers) to silicon photomultipliers (SiPM). 32 SiPM signals are transmitted to an electronic readout board based on a 32-channel ASIC CITIROC 1A. Two layers of 96 strips with orthogonal orientation are combined in a single body of aluminum sheets.

The report discusses the features of CMH's detection system, as well as the results of testing a trial batch of scintillation strips and a trial batch of SIPM at the stands of SEC NEVOD.

Rare decay process of the Higgs boson into a pair of $J/\Psi$ and a pair of $\Upsilon$ mesons is studied within perturbative Standard Model and relativistic quark model. Relativistic corrections to the production amplitudes, connected with the relative motion of heavy quarks, are calculated. Different decay mechanisms are studied. Numerical values of the decay widths of the Higgs boson are obtained, which can be used for comparison with experimental data.

The Jacobson have shown that Gravity force is not fundamental phenomenon and one able to consider it as emergent one. According to his idea, gravity is only the first law of thermodynamics of space-time. The next step in this direction was forwarded by Verlinde whom argued that gravity is not fundamental force and can be interpreted as the entropic force due to changing of entropy associated with the information on the holographic screen. Hence, he derived Newton's law of gravity, the Poisson equation and Einstein's field equations. In Jacobson and Verlinde studies entropy plays the key role. Therefore, modifying entropy expression yields some deviations in Newton’s law of gravity and Evolution of Universe. In this context, by using Renyi entropy expression and with aid of Verlinde argument, Newton’s gravity equation and corrections on Friedmann equations are reconsidered. Also, the second law of thermodynamics of whole Universe is investigated.

Liquid scintillators have always been an important part of many experiments in neutrino physics. Currently, the so called “standard” liquid scintillator consisting of linear alkylbenzene (LAB), 2,5-diphenyloxazole (PPO) and 1,4-Bis(2-methylstyryl)benzene (bis -MSB) is used in many experiments. As an alternative to the “standard” LAB-based liquid scintillator, a new highly efficient liquid scintillator with organosilicon scintillation fluor, so called NOL (Nanostructured Organosilicon Luminophore), was proposed and developed. The light yield and emission kinetics of the new LAB-based scintillator with NOL fluor have been extensively characterized and studied. The light yield of the developed liquid scintillator is almost two times higher than that of traditional LAB-based liquid scintillator with PPO fluor. The fastest decay time constant of the emission kinetics is in the range of about 9 to 14 ns, depending on the fluor concentration, and the contribution of the fastest component accounts for 80% of the total light yield. The scintillation parameters have also good long-term stability. The developed liquid scintillators based on LAB and NOL are planned to be used in a prototype of Baksan Large Neutrino Telescope, which is proposed to be constructed at the Baksan Neutrino Observatory.

A central goal of current relativistic heavy-ion experiments is to study the properties of the hot and dense QCD matter. Anisotropic flow measurements of identified particles play an essential role in the constraining transport coefficients of the strongly-coupled Quark Gluon Plasma (sQGP) and studies providing better insight to the QGP phase diagramm.
We report on the results of the recent measurements of anisotropic flow using state-of-the-art models, provide detailed comparison with existing experimental data and discuss them using different scaling relations for azimuthal anisotropy for energies that will be available at Nuclotron and NICA facilities.

A scintillation experiment is a part of the TAIGA astrophysical complex located in the Tunka Valley, 50 km from Lake Baikal. It consists of the Tunka-Grande and TAIGA-Muon arrays. Its scientific program is devoted to the study of cosmic rays (CRs) and search for astrophysical gamma rays by detecting charged particles (electrons and muons) of extensive air showers (EASs).
We present the current status of the scintillation experiment, methods of EAS and CR parameters reconstruction, the main results obtained by the Tunka-Grande array and our scientific program for the future.

Level structure of heavy helium isotope $^{9,10}$He is studied in the reactions of stopped pion absorption $^{14}$C($\pi^-$, p$^4$Нe )X, $^{14}$C($\pi^-$,d$^3$Нe)X, $^{14}$C($\pi^-$,p$^3$Нe)X. The experiment was carried out at the LANL with a two-arm semiconductor spectrometer. The ground and excited states of $^9$He have been observed. The E$_x \approx$ 11 MeV state of $^9$He has been observed for the first time. The indication of the existence of the E$_r \approx$ 7 MeV resonant state of $^{10}$He was obtained. Parameters of excited states have been compared with data of other experimental and theoretical works.

A promising way of studying properties of distant objects and transient sources in the Universe is exploring neutrino coming from that sources. Such transients as Fast Radio Bursts (FRB) are of particular interest for astroparticle physics. FRB is a millisecond radio transient observed at extragalactic or cosmological distance. Numerous models with a wide variety of physical processes have been proposed to explain the origin of FRBs. Some of these models predict an low-energy neutrino emission from FRB. The most sensitive tool for studying neutrino with energies in the region 250 keV - 10 MeV is the Borexino detector, a unique 300 t mass low-background scintillator detector operated in the Gran Sasso Laboratory.

In the current work the search for signals with visible energies above 250 keV within a time window of ±1000 s centered at the detection time of 42 most intensive FRBs is described. An alternative approach based on search for specific shapes of neutrino-electron scattering spectra in the full exposure data of the Borexino detector have also been applied. As a result the strongest upper limits on the FRB-associated fluences of all flavors neutrino have been obtained.

The paper presents the methodology and analysis of experimental data obtained by a Large Volume Detector (LVD) located in the Gran Sasso Laboratory. For 30 years of the experiment, a large database has been collected, on the basis of which a limit has been set on the frequency of supernova explosions in the Galaxy.

A gaseous beam monitor is being developed for the CSR external-target experiment (CEE) at HIRFL. The requirements on the beam particle rate of up to $10^{6}$ pps and the per-particle position resolution of better than 50 $\mu$m pose challenge on the detector design. The beam monitor mainly consists of two drift chambers, each measuring a 1D position of the beam particle transverse to the beam direction. The detector simulation has been carried out to optimize the geometrical set-up, to evaluate the expected performance, and to calculate the requirements on the custom-designed charge sensor. We will present the simulation studies of the beam monitor, which is mainly based on the Geant4, Garfield++ and COMSOL softwares. A preliminary study of the space charge effect due to the beam particles will also be discussed.

The LHC Phase II Upgrade foreseen for 2026 implies multi fold increasing of number of collisions and radiation levels compared to the present LHC conditions. The electromagnetic calorimeter (ECAL) of LHCb experiment requires modernisation due to enlarged radiation doses and high occupancy: replacing shashlik-type modules for the central part by spaghetti-type (SPACAL) calorimeter. Current paper presents results of the material optimisation (fibres diameter and distance between their centres (pitch), absorber material) for lead-polystyrene SPACAL module performed with GEANT4 simulation to satisfy the LHCb requirements in term of energy resolution.

Measurement of π0 yield is an important part of analysis of heavy ion collisions data. The momentum and angular distributions of π0 provide information about thermodynamic properties of the hadronic matter right after the chemical and kinetic freez-out. Also these measurements play an important role in reducing the systematic uncertainties in study of dilepton spectra.
The decay π0 → γγ has 99% branching ratio and thus provides the best statistics for such analysis. The Ag + Ag data at the beam energy 1.23 A GeV have been studied. The events with centrality 0-30 % were selected for the analysis. The procedure of π0 yield determination is discussed in this talk. It includes calibration of the involved detector, its acceptance and efficiency corrections. Particular attention is paid on studying the systematic uncertainty of these measurements.

To study physical observables in the BM@N experiment, it is extremely important to have a model that can describe the data well. The BM@N experiment will have a new collection of the collision data for Xe+CsI@3.9 AGeV. The Scintillation Wall is one of the detectors of the BM@N experiment installed in front of the forward hadron calorimeter and designed to measure the distributions of charged fragments. Modeling the charge distributions of fragments on this detector will make it possible to compare them with experimental distributions and also use them to determine centrality. The comparison of the charge distributions in the Scintillation Wall using DCM-SMM, PHQMD-SACA and PHQMD-MST generators has been done.

In the early stages of the core-collapse supernova a prominent amount of neutrinos is emitted in a short burst on a ~10s time scale.
Since the neutrinos can escape the medium of the collapsing star without interaction, such signal can be detected by the neutrino experiments several hours before the observable optical signals.

SuperNova Early Warning System (SNEWS) is an international network of neutrino experiments, aiming at the real-time search for a supernova neutrino signal for providing the early warning of galactic supernova.
This system has been operating since 1998, providing an automatic server in a simple coincidence mode sending an alert when two detectors register an excess of events within a certain time window.

We report the status of an ongoing major upgrade of the SNEWS system, which includes studying possible neutrino signals, applying more advanced coincidence techniques, accounting for directional information and a search for pre-supernova neutrino signal.

The anomalous effect discovered in the PAMELA experiment[1] and confirmed by subsequent cosmic ray experiments consists in a sharp increase of the fraction of galactic positrons over much of energy range 1.5 - 100 GeV, which contradicts theoretical predictions. To study this effect, a new experiment for detecting high-energy electrons and positrons using synchrotron radiation in the geomagnetic field was proposed[2].

In this work, we simulated the operation of a detector for different satellite orbits and orientations. The counting rate of the detector located in the polar orbits at an altitude of 400 km above the Earth's surface for positrons in the energy range 1 - 10 TeV has been estimated.

[1] O. Adriani, G. C. Barbarino, G. A. Bazilevskaya // An anomalous
positron abundance in cosmic rays with energies 1.5–100 GeV // Nature,
2 April 2009.

[2] A. M. Galper, S. V. Koldashov, V. V. Mikhailov and O. F. Prilutskii // High energy positron detection via synchrotron emission in magnetosphere // Journal of Physics: Conference Series, Volume 798, International Conference on Particle Physics and Astrophysics, 10–14 October 2016.

The study of the proton transfer process during the interaction of accelerated nuclei with light nuclei near the Coulomb barrier is of great interest for astrophysics, since the information obtained from the analysis of such reactions makes it possible to estimate the astrophysical S-factors of the radiative capture of protons at very low energies, where direct measurements are impossible.
For example, from the analysis of the ${\rm^{27}Al}({\rm^{3}He},{\rm^{}d}){\rm^{28}Si}$ reaction, one can extract the squared ANCs $C\rm^{2}({\rm^{28}Si}\rightarrow {\rm^{27}Al+p})={C\rm^{2}_{271}}$ of the overlap functions ${\rm^{28}Si}\rightarrow {\rm^{27}Al+p}$ for all proton bound states in the ${\rm^{28}Si}$ nucleus. It allows one to calculate the direct part of the astrophysical S-factor for the ${\rm^{27}Al}({\rm^{}p},{\rm^{}\gamma}){\rm^{28}Si}$ reaction The excitation energies of the ${\rm^{28}Si\rm^*}$ nucleus are high when a proton is captured ($s_p=11.585 MeV$), and several resonances contribute to the total S-factor when even a low-energy proton is captured. At the same time, in order to calculate the contribution of the direct process to the total astrophysical S-factor of the ${\rm^{27}Al}({\rm^{}p},{\rm^{}\gamma}){\rm^{28}Si}$ reaction, in reality it is possible to take into account the ANC values only for strongly excited proton bound states in the ${\rm^{28}Si\rm^*}$ nucleus.
At that, in order to evalulate the contribution of the direct process to the total astrophysical S-factor of the ${\rm^{27}Al}({\rm^{}p},{\rm^{}\gamma}){\rm^{28}Si}$ reaction, in reality it is possible to take into account the ANC values only for strongly excited proton bound states in the ${\rm^{28}Si\rm^*}$ nucleus.
To extract the ANC values of the proton bond in the ground ($0\rm^+$) and excited (E=1.778 MeV, $2\rm^+$), (E=4.618 MeV, $4\rm^+$) states of the ${\rm^{28}Si}$ nucleus from the angular distributions of the DCS of proton transfer reactions
(${\rm^{3}He},{\rm^{}d}$), we performed analysis of these data within the framework of the DWBA..
An analysis of the experimental DCS of the ${\rm^{27}Al}({\rm^{3}He},{\rm^{}d}){\rm^{28}Si}$ reaction at the energies E=25 MeV [1] and 37.7 MeV [2] in the frameworks of modified DWBA was made. The ANC values for the ground and excited states of ${\rm^{28}Si}$ were obtained. Selection of sets of the optical model parameters for the input and output channels of these reactions was performed using literature data, including the recommended OP given in the papers with the corresponding experimental data.

References:
1. J. Vernotte, et al. Nuclear Physics A571 ( 1994).
2. R.W. Barnard et al. Nuclear Physics A108 (1968).

The iDREAM (industrial Detector of Reactor Antineutrinos for Monitoring) has been developed as a prototype of the industrial detector for development reactor monitoring methods. The detector has been installed and commissioned at Kalinin NPP (Russia) at 20 m from the 3 GWth reactor core (third unit). The detector is a scintillator spectrometer. The calibration measurements play a crucial role for the further antineutrino analysis. A unique calibration system has been developed, which allows positioning a source along a vertical axis of the detector with a 2 mm precision. The calibrations with gamma-sources and a source of fast neutrons have been conducted on a regular basis.

The d+d reaction is very well suited for calibration due to the 2.45 MeV fast neutron reaction channel. Due to this circumstance, the d+d neutron generator is considered as one of the promising tools for calibrating low-background neutrino and dark matter detectors [1]. The current status of the development of a compact neutron generator is presented. The generator includes the elements of the Pierce electron gun, magnetic elements for effective ion generation and the target assembly at a positive potential. Unlike previous versions [2-5], the current version of the neutron generator allows obtaining a stable and controllable low neutron flux (100-1000 particles per second per full solid angle).
The current design of a compact neutron generator, a computer model of the electric field and ion flux are presented. The results of the ion current and neutron flux measurement under various conditions are discussed.

The work was financially supported by a Program of the Ministry of Education and Science of the Russian Federation for higher education establishments, project No. FZWG-2020-0032 (2019-1569).

References
[1] F. N. Beg et al., Appl. Phys. Lett. 80, 3009 (2002)
[2] A.S. Chepurnov et al., 2017 J. Phys.: Conf. Ser. 798 012119
[3] A.S. Chepurnov et al., 2017 J. Phys.: Conf. Ser. 934 012013.
[4] A.S. Chepurnov et al., 2018 JINST 13 C02035
[5] A.S. Chepurnov et al., 2019, J. Phys.: Conf. Ser 1390 012103.

The aim of this work is to study the cross-section of the inelastic interactions of nuclei with tungsten based on the data of PAMELA space experiment [1]. This instrument is a magnetic spectrometer designed to study fluxes of charged particles in cosmic rays, which was launched into the near-Earth orbit aboard the ResursDK1 satellite; data collection continued from 2006 to 2016. PAMELA includes a set of detectors which helps to identify the particles including their magnitude and sign of charge, rigidity, velocity, mass and energy. So, we can select from the PAMELA data a necessary component of cosmic rays with known particles and their energy coming at a known angle. At the same time, another detector - a coordinate-sensitive calorimeter with a tungsten absorber plays a role of target for these particles. This looks like an experiment in particle physics on accelerators with formation of a beam of particles and observation of its interaction in target. Thus, it becomes possible to study the characteristics of nuclear-nuclear interactions with a large number of different nuclei in a beam according to chemical composition of cosmic rays in a wide energy range from hundreds of MeV to ˜TeV. A similar method is used in ground-based observations of ultrahigh-energy cosmic rays; however, in this work, we use the previously proposed method relies on a much larger amount of information about cosmic ray particles due to the precision nature of the PAMELA measurements [2]. In the report, we present the experimental cross sections for the interaction of nuclei from protons to carbon with tungsten nuclei obtained by the described method. Obtained results compared with the cross-sections reconstructed from the simulation data coming from Geant4 software package [3], with measurements at accelerators and existing theoretical models. Results can be used to improve our knowledges about nuclear forces and expand the standard Geant4 hadronic models and other numerical packages describing the interaction of particles with matter.

1. O. Adriani, G. Barbarino, G.A. Bazilevskaya et al, PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysicsg, Astroparticle Physics, V.27, 2007.
2. О. Голуб, А. Майоров, Определение сечения неупругого взаимодействия протонов и ядер гелия с вольфрамом по данным космического эксперимента PAMELA, Учен. зап. физ. фак-та Моск. ун-та. 2019
3. S. Agostinelli et al., Geant4 - A Simulation Toolkit, Nucl. Instrum. Meth. A 506, 2003.

We consider the interaction of particles with domain walls in the early Universe. The domain wall is a topological soliton of a scalar field. We obtain quantitative estimates for transmission and reflection coefficients using various approximate expressions for the effective potential of interaction.

The Electron String Ion Source (ESIS) is a relatively novel type of ion source, which is under development since 1994, when the electron string phenomenon was first observed. ESIS is a sophisticated modification of Electron Beam Ion Source (EBIS) working in a reflex mode of operation under specific conditions, the operation is based on step-by-step ionization of the ions by hitting with electrons of an electron string.
ESIS is a complex facility, so the electronic control system is crucial.
Globally, the KRION 6T source electronics systems can be divided into two parts – the slow control system and the ion motion control system. The slow control system combines the following monitoring and control elements: the electron gun and the ions extractor; the magnetic optics; vacuum and temperature monitoring; the locking system; the beam diagnostic.
The basis of ionization process in ESIS is an electron beam produced by the cathode electronics assembly.
The new cathode electronics assembly contains several interesting electronic modules which are designed by the JINR NICA accelerator division engineers.
The topic describes the ESIS electronics development, production and operation process.

The background induced by misidentification of a jet as a photon ($jet\rightarrow\gamma$) is usually estimated using two-dimensional sideband method (ABCD-method) in collider experiments. This report is devoted to an alternative "slice method" of the estimation based on likelihood fit of $jet\rightarrow\gamma$, signal and other background yields using kinematic distributions in a phase-space region with relaxed requirements on corresponding variables. This method does not require optimization of regions definition, which results in much faster estimation. One of the main advantages of the considered method is that it takes into account data, signal and all other backgrounds distributions. It also takes into account the dependency on isolation. Both of these factors allow better estimation accuracy. The estimates of the considered method are confirmed by the standard ABCD-method.

The problem of dark matter particle search is at the frontier of the modern physics. The scenario of composite dark matter, in which hypothetical, stable, lepton-like particles X having a charge - 2n, where n is any natural number, and forming neutral atom-like states of X-helium with primary helium nuclei, called "dark" atoms, offer a solution to the problem of direct searches for dark matter particles. The solution of the problem is connected with a rigorous proof of the existence of a low-energy bound state in the interaction of a dark atom with a nucleus, which requires a self-consistent description of nuclear attraction and Coulomb repulsion in such an interaction. As part of our approach, we use numerical modeling to describe the dark atom interaction of with nuclei and study the features of such interaction. Considering the classical three-body problem, we consistently add the effects of quantum physics to more accurately describe this interaction.

The spatial parity (P) violation in strong interactions have never been observed experimentally. One can include a P-breaking term in the QCD lagrangian. Thus, there can be a local violation of P-symmetry in the medium with hight temperature and large topological fluctuations [1]. As a consequence, some hadrons would decay in channels that forbidden by the global parity conservation [2]. In this work we investigate the possibility of observing such process: decay of a charged $a_0$ meson into charged pion and photon [3]. We study an invariant-mass spectrum of $\pi^\pm - \gamma$ pairs produced in PYTHIA Monte Carlo generator with enabled $a_0^\pm \rightarrow \pi^\pm + \gamma$ decay channel. To distinguish the peak of mentioned decay from the background the mixed-event substracting, kinematic cuts and Dalitz plots analysis was used. As a result we have estimated minimal number of pp collision events for signifacant signal of the P-breaking decay.

The study was funded by the Russian Science Foundation grant No.
22-22-00493,
https://rscf.ru/en/project/22-22-00493/

References:

[1] D. Kharzeev, Annals of Physics, 325, 1. 205 – 218 (2010).

[2] A.Andrianov, D.Espriu and X.Planells, Eur. Phys.J. C73 (2013) no.1, 2294

[3] A. Andrianov et al, EPJ Web of Conferences 158, 03012 (2017).

The binary black hole coalescences GW150914 and GW151226 observed by the LIGO enabled us to investigate gravity in the strong-field regime. In the formation models, including isolated binary stars, there are still many open questions about the sustainability of mass transfer and common envelope evolution. The gravitational wave (GW) sources have been predicted using extensive binary population simulations. We model the galactic population of compact binaries with the "Binary Population Synthesis" method using COSMIC and GW signals. The population's ultimate fate has been predicted based on metallicity. The formation characteristics of the final mass depend strongly on the initial mass and the metallicity associated with a system-defined critical point.

The aim of the poster is to demonstrate status of the work in estimation of NA62 [1] experiment sensitivity towards the search for forbidden decay $\pi^{0}\rightarrow3\gamma$ and rare decay $\pi^{0}\rightarrow4\gamma$. Current branching-ratio upper limit is $3.1\times10^{-8}\:(90\%\;\textrm{C.L.})$ for the $\pi^{0}\rightarrow3\gamma$ decay and $2\times10^{-8}\:(90\%\;\textrm{C.L.})$ for $\pi^{0}\rightarrow4\gamma$ decay established in Los Alamos National Laboratory [2].

$K^{+}\rightarrow\pi^{+}\pi^{0}$ decays were used as a source of $\pi^{0}$. Selection criteria for events with 3 or 4 products after $\pi^{0}$ decay in NA62 detector were developed. NA62 detector and all physical processes were modelled with Monte Carlo method using Geant4. Estimation of experiment sensitivity without background events consideration is 1 order better, than current upper limit for $\pi^{0}\rightarrow3\gamma$ and $\pi^{0}\rightarrow4\gamma$ decays. Background processes for both decays were studied. Main contribution in background events is $K^{+}\rightarrow\pi^{+}\pi^{0}, \pi^{0}\rightarrow2\gamma$ decay, when photon interacts with detector, and $e^{+}e^{-}$ pair is created. Comparison of Monte Carlo simulation and experimental data was done. The estimation of number of background events inside signal region was obtained.

Literature:

1. Cortina Gil E., et al. The Beam and detector of the NA62 experiment at CERN // JINST 2017. V. 12. P05025

2. McDonough J., et al. New searches for the C-noninvariant decay $\pi^{0}\rightarrow3\gamma$ and the rare decay $\pi^{0}\rightarrow4\gamma$// Phys. Rev. D 38(1988), 2121

The report focuses on studying the semiclassical limit in the case of a closed isotropic model with a scalar field, decomposed into modes. The calculations are made within frameworks of two approaches. The first is the Wheeler-DeWitt quantum geometrodynamics, and the second is the extended phase space approach, that is known to be gauge dependent. The work is aimed in comparing results, obtained within the scopes of these approaches. The transition to the semiclassical limit is implemented by using the Born-Oppenheimer type of approximation. The expansion parameter is chosen to be M=c^3/16πG, that is analogous to the coefficient in expression for the classical action of gravitational field. It is shown that computations in present case differ from the ones in the case of homogeneous scalar field, and we have to make changes in approximation scheme for obtaining adequate results. In the both approaches, O(1/M) order of the approximation corresponds to a Schrödinger equation with quantum gravitational corrections. The obtained equations coincide if we choose the lapse function N=1. Next, the question of unitary evolution is discussed. In present work we follow the method used in works by Kiefer and Singh, so corrections terms have non-unitary character. This circumstance can be avoided by using other technique, for instance, the one proposed by Maniccia and Montani.

The Fast Interaction Trigger (FIT) is used as an interaction trigger, luminometer, the first indicator of the vertex position, and the forward multiplicity counter of the ALICE experiment at CERN during Run 3 of the LHC. The FIT consists of three subsystems: FT0 – a set of two fast Cherenkov arrays, FV0 – a large segmented scintillator disk and FDD (Forward Diffractive Detector) – also a scintillator located at very high pseudorapidity. All three subsystems (FT0, FV0 and FDD) use a single design of the front-end electronics with CFD, TDC and ADC parts. The collected data is processed in FPGA. Hit time measurements are done relative to the LHC high-quality clock with a time resolution of ~50ps. FIT FEE connected to ALICE DAQ with GBT links for timestamps distribution and measured data sending. The time synchronization concept of the FIT detector with ALICE DAQ, clock drift compensation mechanism and time alignment procedure will be shown.

The Tunka-Grande scintillation array is a part of the TAIGA experimental complex, located in the Tunka Valley (Buryatia Republic, Russia). The array is intended to study the energy spectrum and the mass composition of charged cosmic rays and search for diffuse gamma rays above 10 PeV by detecting charged components of extensive air showers. This report describes the current state of the array simulations based on the CORSIKA and Geant4 toolkits, as well as some of the results obtained from the simulations. We also present future prospects for the Tunka-Grande simulations in the context of measurement of the primary mass composition in the 10 - 1000 PeV energy range.

Ultra-high energy cosmic rays (UHECR) can be produced in active galaxies, and directional correlations between them were studied extensively. One puzzling result was the correlations of arrival directions of UHECR and a particular class of active galactic nuclei, BL Lacertae type objects, discovered in 2004 with the HiRes stereo data set [1,2]. If confirmed, this result would definitely mean new physics or very unconventional astrophysics because it implies neutral particles travelling for cosmological distances. However, the HiRes resolution remains unsurpassed, and the hypothesis has not yet been tested with independent data. The original correlations [1] used the catalog [3] which is not complete by any criteria. Even though statistical methods of analysis were selected to minimize the associated uncertainties, random biases still could have affected the result. That’s why it is needed to repeat this analysis with the use of a complete sample of sources. This report is dedicated to the methods used in construction of such a complete and isotropic set of BL Lacs adopted for future tests of the enigmatic correlations with the new data of the Telescope Array experiment.

[1] – D. S. Gorbunov, P. G. Tinyakov, I. I. Tkachev, S. V. Troitsky, arXiv:astro-ph/0406654v1

[2] – HiRes Collaboration 2005

[3] – M. P. V´eron-Cetty and P. V´eron, ESO scientific report (2000); M. P. V´eron-Cetty and P. V´eron, Astron. Astrophys. 374 (2001) 92.

A short introduction to Weyl geometry and Weyl gravity is given. The self-consistency relation for the variation of the general form of the matter action integral to be conformal invariant is obtained. It is shown that the particle production rate per unit coordinate volume per unit coordinate time is conformal invariant. It is noticed that such a feature allows us to consider the perfect fluid action as an example of the Sakharov’s induced gravity model.

The geodesic deviation equation
$\frac{D^2\xi^{\mu}}{d\tau^2}=R^{\mu}_{.\nu\alpha\beta}u^{\nu}u^{\alpha}\xi^{\beta}$, where $u^\mu$ is 4-velocity vector tangent to geodesic and $\xi^\mu$ is geodesic deviation vector, which connects two points corresponding to the same value of the affine parameter $\tau$ on two close geodesics, was studied in multidimensional Tangherlini spacetime with line element

$ds^2=g_{\mu\nu}dx^{\mu}dx^{\nu}=f(r)dt^{2}-\frac{dr^2}{f(r)}-r^2d\Omega^2_{D-2},$

where $d\Omega^2_{D-2}$ and $f(r)$ are

$d\Omega^2_{D-2}=d\theta^2_1+\sum\limits_{j=2}^{D-2}d\theta^2_j\left(\prod\limits_{k=1}^{j-1}\sin^2\theta_k\right),\; f(r)=1-\frac{\mu_D}{r^{D-3}}+\frac{q_D^2}{r^{2(D-3)}},$

where $\mu_D$ and $q_D$ are proportional to the mass and charge of the black hole. We have constructed a basis set of vectors, with respect to which the equation acquires a diagonal form. In the case of radial geodesics, when the angular momentum $L$ is zero, all spatial components of the equation can be explicitly integrated by quadratures. Their local behaviour are $\xi^r\propto\frac{1}{r^{D-3}}$, $\xi^a\propto r$, $a=\theta_1,..,\theta_{D-2}$. But in the case of non-radial geodesics we constructed solutions of spatial components geodesic deviation equation in the vicinity of physical singularity using Fromebius method for Fuchs class equation in form of power series. This made it possible to determine that solutions in the main order have form $\xi^r\propto\frac{1}{r^{D-3}}$, $\xi^a\propto r$, $\xi^{\theta_{D-2}}\propto const$, $a=\theta_1,..,\theta_{D-3}$. This allows us to conclude that the tidal stretching of the test object along the radial direction depends on the spacetime dimension, while the tidal compression along the transverse directions in the leading order does not depend on the dimension.

The question about the appearance of time in the semiclassical limit of quantum gravity continues to be discussed in the literature. It is believed that a temporal Schrödinger equation for matter fields on the background of a classical gravitational field must be true. To obtain this equation, the Born – Oppenheimer approximation for gravity is used. However, the origin of time in this equation is different in works of various authors. For example, in the papers of Kiefer and his collaborators, time is a parameter along a classical trajectory of gravitational field; in the works of Montani and his collaborators the origin of time is introducing the Kuchař – Torre reference fluid; in the extended phase space approach the origin of time is the consequence of existing of the observer in a fixed reference frame. We discuss and compare these approaches. However, none of the approaches can explain how time had appeared in the Early Universe, since it is supposed that classical gravity and, therefore, classical spacetime had already come into being.

A successful compactification scenario should explain two, in principle, rather different properties of the multidimensional space-time. First, we need to show why the evolution of three big dimension is different from the evolution of other dimensions. Second, we need to explain why the 3-dimension subspace is almost isotropic one. We present a scenario which address both issures. Starting from rather general totally anisotropic initial condition the evolution of a Universe naturally leads to a product of two isotropic subspaces. This presentation is a brief summary of a set of papers made in collaboration with A.Giakomini, S.Pavluchenko and D. Chirkov.

We consider $f(R)$ gravity model with an additional function of the Gauss-Bonnet term.
We analyze the model in slow-roll regime and estimate inflationary parameters using observational
data to restrict parameters including to the function of the Gauss-Bonnet term.

Probably, physics of particles must consist of two parts. Low energy -standard model. High energy > $\ 10^{5}$ GeV - the early Universe.The first step to modernization of Standard model is insertion of quarks with electric charges q=$-\frac{2}{3}$ and q=$\frac {1}{3}$ in its high energy part. During baryon genesis has deternined the quark composition of protons and neutrons.Baryon genesis was realized on energies $\sim 10^{2}$ -$\ 10^{3}$ GeV fixed baryon asymmetry after decay of the competition reaction. Besides, the composite model of elementary particles is more acceptable with cosmological point of view because of its consequences are printed in baryon large scale structure of the Universe.

We discuss evolution of 4-dim manifold endowed by 2-dim compact extra dimensions The first step is finished by de-Sitter stage at high energies. The quantum fluctuations destroy initial symmetry of extra space metric producing a wide range
of the initial extra metrics in causally disconnected regions (pocket universes) of the Multiverse during the second step. This set of different
extra metrics evolves to a final set. The symmetry and form of each final
extra metric is specific for each pocket universe. The low energy physics
appears to be different in different pocket universes. The numerical esti-
mation of the probability of finding a specific metric is based on the model
of compact 2-dimensional extra space

We consider modified gravity cosmological models that can be transformed into two-field chiral cosmological models by the conformal metric transformation. For the $R^2$ gravity model with an additional scalar field and the corresponding two-field model with the cosmological constant and nonstandard kinetic part of the action, the general solutions have been obtained in the spatially flat FLRW metric. We analyze the correspondence of the cosmic time solutions obtained and different possible evolutions of the Hubble parameters in the Einstein and Jordan frames.

This talk is based on the paper [1].

[1] Vsevolod R. Ivanov and Sergey Yu Vernov. Integrable modified gravity cosmological models with an additional scalar field. European Physical Journal C, 81(11):985, 2021.

FASER is a new experiment at the CERN LHC which is located on the beam
collision axis line-of-sight 480 m from the ATLAS collision point in
unused service tunnel, TI12. The quite compact detector is designed to
search for light and very weakly-interacting new particles produced in the LHC collisions. The additional FASERnu emulsion sub-detector allows
to detect and study neutrinos of all flavours produced at LHC. The
detector has been successfully installed and is taking data during the LHC
Run 3. Details on physics prospects, detector
design, commissioning status and first recorded data will be given in
this talk.

The NA64 experiment is a fixed-target experiment at the CERN SPS combining the active beam dump and missing energy techniques to search for rare events by colliding 100-150 GeV energy electron or muon beams onto an active target.
The talk presents the muon part of the experiment. The NA64-mu looks for the muon (g-2) anomaly and light dark matter with the semi-visible dark photon channel. The present report shows the status of the experiment, the theoretical and experimental parts, and future goals

The Higgs boson in its vector boson fusion production mode and its decay to a pair of W bosons that in turn decay leptonically to a eνμν final state, is probed. The Large Hadron Collider delivered proton-proton collisions at a center-of-mass energy of 13 TeV between 2015 and 2018 which were recorded by the ATLAS detector, corresponding to an integrated luminosity of 139 fb−1. Deep Neural Network is exploited in the analysis. The total cross section for Higgs boson production by vector-boson fusion times the H→WW∗ branching ratio is measured to be 0.75+0.19−0.16 pb. The results are consistent with Standard Model expectations of 0.81±0.02 pb

Higgs boson production via gluon-gluon fusion in proton-proton collisions is measured in the H→WW∗→eνμν decay channel. The utilized dataset is the √s=13 TeV proton-proton collision data collected by the ATLAS experiment during Run 2 of the Large Hadron Collider with an integrated luminosity of 139 fb−1. The total cross section for Higgs boson production by gluon-gluon fusion times the H→WW∗ branching ratio is measured to be 12.0±1.4 pb, in agreement with the Standard Model predictions of 10.4±0.6 pb. Higgs boson production is further characterized through measurements of Simplified Template Cross Sections in a total of 6 kinematical fiducial regions for the considered mode.

The search for anomalous couplings is an indirect model-independent way to find deviations from the Standard Model (SM). Effective field theory allows to parameterize these anomalous couplings in the Lagrangian, respecting the SM gauge symmetries, using operators of higher dimensions constructed from the SM fields. In the classical way of setting the limits on the operators (Wilson) coefficients, it is assumed, that beyond-the-Standard-Model contributions come from the signal process only. However, one or several backgrounds can be also affected by non-zero Wilson coefficients, leading to corrections of the resulting limits on the Wilson coefficients. In this work the corrections are estimated for neutral triple gauge boson coupling limits from $Z(\nu\bar{\nu})\gamma$ production at the conditions of the ATLAS experiment, since this process is extremely sensitive to such anomalous couplings. The corrections are found to be significant and improve the limits on the Wilson coefficients.

A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton-proton collision data at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2016-2018, corresponding to an integrated luminosity of 137 fb$^{−1}$. The search uses the decay channels Z → ee and Z → μμ. No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. The results of preparation for RUN3 analysis are also discussed.

We discuss a limits on a hidden sector models, which have been excluded recently by NA64e that is the electron fixed-target experiment at CERN SPS. Namely, new experimental bounds on Dark Photon, millicharged fermions and axion-like particles are obtained from the missing energy signatures of the electron beam incident on a lead target of NA64e.

Higher-order QCD predictions of charge asymmetry distributions are presented for inclusive W±+X→l±ν+X production in proton-proton (pp) collisions at 8, 13, and 14 TeV center-of-mass energies. The W boson or the decay lepton charge asymmetries constitute a direct probe of the relative u and d quark distributions in the proton as functions of the initial-state parton momentum fractions. The predictions for the charge asymmetry distributions are acquired at next-to-next-to-leading order (NNLO) accuracy in the perturbative QCD domain, exploiting several parton distribution function (PDF) models. The predicted lepton charge asymmetry distributions are justified with the 8 TeV measurements by the LHC experiments in both central and forward acceptance regions of the lepton pseudorapidities 0≤ηl≤2.4 and 2.0≤ηl≤4.25, and are provided thoroughly for both the regions at 13 and 14 TeV pp collisions energies. Additionally, the impact of various lepton transverse momentum plT thresholds on the lepton (or the W boson) charge asymmetry predictions at NNLO accuracy are presented in the fiducial region encompassing both central and forward detector acceptances of the lepton pseudorapidity 0≤ηl≤4.5. The lepton and W boson charge asymmetry distributions are assessed to be in close correlation with the plT threshold, where the distributions are particularly observed to be more correlated at a higher-plT threshold. The W boson asymmetry distribution as a function of the W boson transverse momentum pWT is also presented with improved accuracy by matching the NNLO predictions to resummed logarithmic corrections. Overall, the predicted results represent a substantial contribution in the context of the high-precision phenomenological studies.

A specific representation of the known one-loop EW correction to the relation between the pole and running $\msbar$-scheme masses of the top-quark through particle masses of the Standard Model is given within the Fleischer-Jegerlehner tadpole scheme, where the vacuum expectation value of the Higgs field is renormalized. The importance of taking into account both the EW and QCD effects in this relation in the considered case is emphasized. It is noted that the discard of the EW corrections leads to over 10GeV shift in the difference between the pole and running t-quark masses. This magnitude exceeds essentially the modern uncertainties of the considered relation, following from the treatment of the Tevatron and LHC data where both pole and running t-quark masses are defined in the widespread approach when only the QCD corrections are kept in mind between them. Three other theoretical schemes of defining vacuum expectation value of the Higgs field are considereds. It is shown that in these schemes the 1-loop EW huge effects are essentially minimized. The relation to the recent results of extraction of the top-quark running mass values from CMS and ATLAS data are discussed.

We investigate nonlinear response of the physical vacuum by the example of the third harmonic in radiation of the electron-positron-photon (EPP) plasma exciting by a strong time dependent electric field at the focus spot of counterpropagating laser pulses. The investigation was developed within the framework of the Bogoliubov-Born-Green-Kirkwood-Yvon kinetic theory [1,2] describing nonperturbatively vacuum creation of the electron-positron (EP) quasiparticle plasma (reviews [3-5]) and different channels its interaction with the photon subsystem in the single-photon approximation that are opened in the presence of a strong semiclassical field [6]. The corresponding closed self-consistent system of kinetic equations for the EP and photon subsystems is intended for description of the single-photon annihilation (pair production) and emission (absorption) processes.

Some preliminary results on this basis were obtained in the works [1,2] in the infrared region of the radiation in the annihilation channel (see also [7]). In the present report we show the results of detailed study of the third harmonic on the frequency of laser field in the spectrum of induced quantum radiation of the EPP plasma and compare it with the third harmonic in the radiation of the semi-classical field induced by inner plasma currents [8].

[1] D. B. Blaschke, V. V. Dmitriev, G. Roepke, and S. A. Smolyansky. Phys. Rev. D 84, 085028 (2011).

[2] S. A. Smolyansky, A. D. Panferov, S. O. Pirogov, and A. M. Fedotov. arXiv:1901.02305.

[3] A. Otto, T. Nousch, D. Seipt, B. Kaempfer, D. Blaschke, A. D. Panferov, S. A. Smolyansky and A. I. Titov. J. Plasma Phys. 82, 655820301 (2016).

[4] D. B. Blaschke, A. V. Prozorkevich, G. Roepke, S. M. Schmidt, D. S. Shkirmanov, and S. A. Smolyansky. Eur. Phys. J. D55, 341 (2009).

[5] I. A. Aleksandrov, V. V. Dmitriev, D. G. Sevostyanov, and S. A. Smolyansky. Eur. Phys. J. Special Topics 229. 3469 (2020).

[6] S. A. Smolyansky, A. M. Fedotov, V. V. Dmitriev. Mod. Phys. Lett.A35, 2040028 (2020).

[7] A. Otto and B. Kaempfer. Phys, Rev. D 95, 125007 (2017).

[8] I. A. Aleksandrov, A. D. Panferov, and S.A. Smolyansky. Phys. Rev. A 103, 053107 (2021).

Non-diagonal two-point vector-tensor and tensor-tensor correlator of fermionic currents are calculated in a constant homogeneous magnetic field background. The crossed-field limit of these correlators is presented. The tensor current is a fermionic part of the Pauli Lagrangian density describing the electromagnetic interaction of fermions through their anomalous magnetic moment (AMM). Under assumption that this interaction enters the effective QED Lagrangian, the contribution induced by AMM to the photon polarization operator is calculated and discussed.

We consider dynamics of the massive minimally coupled scalar field theory in an expanding Friedmann-Lemaitre-Robertson-Walker universe. We consider the standard toy model of the conformally flat space-time where the conformal factor becomes constant at the distant past and the distant future. Employing Schwinger-Keldysh diagrammatic technique, we compute infrared loop corrections to the occupation number and anomalous quantum average of the scalar field and show that these corrections are growing with time. Using these observations, we demonstrate that the regularized stress-energy tensor at the distant future acquires substantial quantum corrections which exceed the long known tree-level contributions to the particle flux.

One-loop electroweak radiative corrections to dilepton production in hadron collisions via photon fusion for Large Hadron Collider (LHC) experimental program are estimated, the most attention is paid to hard bremstrahlung. Discussed reaction follows the Drell-Yan process, its studying is the actual task of LHC experimental program. Detailed numerical analysis of electroweak radiative effects to observable quantities (cross sections and forward-backward asymmetry) in wide kinematical region including the CMS LHC experiment in Run3/HL regime corresponding ultra-high energies and dilepton invariant masses is performed.

The lowest order radiative corrections to the lepton current in polarized SIDIS are calculated exactly. The contribution of exclusive radiative tail for polarized initial particles are estimated for the first time. Numerical analysis is performed in the frame of the modern JLab kinematic conditions within Wandzura-Wilczek model for SiDIS structure functions and the exclusive radiative tail is estimated using MAID 2007.

Free particles carrying orbital angular momentum (OAM) are called twisted particles. The wave function of such particles has a characteristic phase $e^{i l\varphi}$, where $l$ is the OAM projection onto the axis along the particle motion and $\varphi$ is the azimuth angle of a point of a wave packet in the cylindrical system of coordinates. The twisted neutrons have been obtained relatively recently, in 2015 [1], by using a phasophobic plate. The methods for obtaining and detecting twisted neutrons are being actively developed [2,3]. The reason for this is the potential applications of such states. They are able to excite forbidden transitions in nuclei that can be employed in nuclear physics. Another promising application of such neutrons is the neutron diffraction. Due to the OAM the twisted neutrons have a higher resolution and sensitivity to magnetic properties of matter. The processes involving neutrons with nonzero OAM can be used to study the internal structure of the neutron itself.

The available papers on twisted neutron scattering [4,5] and radiation [6,7] show that the features arising in these processes cannot be reduced to quantum effects previously known for plane neutrons. For example, new corrections in radiation proportional to $\frac{(|l|+1)\sigma_{\bot}^{2}}{m^{2}}$, where $\sigma_{\bot}$ is transverse size of wave packet, are typical for the processes with twisted particles [6]. As were noted in [6,7], these and other corrections can be larger by an order of magnitude than the classical contribution.

We have studied the Cherenkov and transition radiations produced when a neutron twisted wave packet traverses a medium translationaryt invariant in the plane perpendicular to the incidence direction. We showed that the quantum effects associated with the neutron OAM and the cross section of the neutron wave packet have the same structure as found in [6]. We have derived the estimates for the number of emitted photons and the energy loss due to radiation. We discuss the possibility of observing the generated radiation and how to use it to determine the shape of the wave packet. The result obtained can be generalized to the case of $N$-particle wave packets using the results of [6,7].

Acknowledgments
This study was supported by the Tomsk State University Development Program (Priority-2030).

References

[1] C.W. Clark et al., Controlling neutron orbital angular momentum, Nature 525, 504 (2015).

[2] D. Sarenac et al., Generation and detection of spin-orbit coupled neutron beams, Proc. Nat. Acad. Sci. USA 116, 20328 (2019).

[3] M.G. Huber, C.W. Clark et al., Experimental Realization of Neutron Helical Waves, https://arxiv.org/abs/2205.06263 (2022).

[4] J.A. Sherwin, Scattering of slow twisted neutrons by ortho- and parahydrogen,
Phys. Let. A 437, 128102 (2022).

[5] A.V. Afanasev, D.V. Karlovets and V.G. Serbo, Schwinger scattering of twisted neutrons by nuclei, Phys. Rev. C 100, 051601(R) (2019).

[6] P.O. Kazinski and G.Yu. Lazarenko, Transition radiation from a Dirac-particle wave packet traversing a mirror, Phys. Rev. A 103, 012216 (2021).

[7] P.O. Kazinski and T.V. Solovyev, Coherent radiation of photons by particle wave packets, Eur. Phys. J. C 82, 790 (2022).

The size of a nucleus defined by the radius of its nucleon (proton and neutron) density distribution and the proton charge distribution is one of the most fundamental and important nuclear characteristics. Nuclear radius determines the basic properties of nuclei and is a consequence of the fundamental features of the strong interaction.
The development of methods of measuring the radii of nuclei in their short-lived excited states led to discovery of new classes of states, which were named “the size isomers”.
Up to now two groups of the size isomers were identified: the excited states with halos ($^{9}$Be, $^{11}$Be, $^{13}$C, $^{13}$N) and some specific alpha cluster states ($^{11}$B, $^{12}$C, $^{13}$C). All the observed states are diluted, however, some indication to possible existence of more compact than the ground states was obtained as well (in $^{13}$C).
The phenomenon of size isomerism occurred to be not a rare one especially if one takes into account that rotational bands are based on some of such states. The structure of size isomers is related with some new features, e.g., rotating halos, halos in continuum, different types of quasimolecular configurations. Some rudimentary signs of alpha particle condensation (a “ghost“of condensate) were observed (in the Hoyle state of $^{12}$C), however, one cannot speak about confirmation of this ambitious theory. Analogs to the Hoyle state are expected in $^{11}$B, $^{13}$C, $^{16}$O, $^{20}$Ne near the $\alpha$-emission thresholds are considered.

In our previous publications [1–4] we discussed various manifestations of a new decay channel of the low excited heavy nuclei called collinear cluster tri-partition (CCT). In the frame of the essentially modified experimental method, additional linear structures corresponding to the relations M1 + M2 = const and M1 – M2 = const for the masses M1 and M2 of the fission fragments (FFs) from 252Cf(sf) detected in the opposite spectrometer arms form the rhombic-like configurations with the vertices corresponding to the magic nuclei. The structures are statistically reliable, they are conditioned by a pronounced and complex correlation between the masses of the FFs measured independently. Possible physical scenario standing behind the structures are discussed.

1. Yu.V. Pyatkov et al., Eur. Phys. J. A. 45, 29 (2010).
2. Yu.V. Pyatkov et al., Eur. Phys. J. A. 48, 94 (2012).
3. Yu.V. Pyatkov et al., Phys. Rev. C. 96, 064606 (2017).
4. Yu.V. Pyatkov et al., Eurasian Journal of Physics and Functional Materials, 4, 13 (2020).

This work presents the results of single and double charge exchange reactions measuring in the fragmentation of carbon ions at the energy of 300 MeV/nucleon. Experimental data were collected at the FRAGM facility and the ITEP-TWAC multi-purpose accelerator complex on a thin beryllium target [1, 2]. The search was made for the following set of isotopes that carried out with nucleon charge exchange: ¹¹Be, ¹²B, ¹²N, ¹²Be. The differential cross sections for the production of these isotopes considered as functions of the fragment momentum [3]. These measurements of the charge exchange processes in this energy range were performed for the first Time. Additionally the upper limit of the ¹²N ions production was also estimated. The obtained data are considered with a comparison of the theoretical ion-ion interaction models. These presented results expand the database on nuclear fragmentation processes that occur with nucleon charge exchange and provide new material for testing the theoretical models.

1. B.M. Abramov et al., Phys. At. Nucl. 78, 373 (2015)
2. B.M. Abramov et al., EPJ Web Conf. 138, 03002 (2017)
3. A.A. Kulikovskaya et al., Yad. Fiz. 85, №5, 339 (2022)

Results of a search for hidden patterns in the behavior of the 214Po half-life solar-daily variation parameters obtained in the data collected in the 2012 – 2015 years are presented. It is shown that amplitude of the sine curve approximated a half-life solar-daily dependence obtained for an each season of the year by an averaging through 90 days could reach 3.3∙10-3 from the daily averaged value. Similar analysis of the data collected in the 2018 – 2022 years for the 213Po showed that the amplitude of a deviation from the averaged value could reach 2.3∙10-3. This effect could limit an accuracy of precise but short time-duration measurements of such short-lived isotopes giving a systematic error. New value of the 213Po half-life is presented.

The formation of the unbound heavy helium isotopes 7,9He was studied in the reactions of stopped pion absorption by light nuclei. The ground and excited states were observed in the following channels: 9Be(pion-,d)7He, 11B(pion-,pt)7He, 10B(pion-,pd)7He, 11B(pion-,pt)7He, 10B(pion-,dd)7He, 12C(pion-,p4He)7He, 12C(pion-,d3He)7He, 14C(pion-,t4He)7He and 11B(pion-,pp)9He, 14C(pion-,p4He)9He, 14C(pion-,d3He)9He. Measurements were carried out using two-arm multilayer semiconductor spectrometer. The data on the level structures obtained in different reaction channels are consistent with each other. Comparison with theoretical and experimental results obtained by other authors was performed. Our results on the energies and widths of the low-lying states of the 7,9He are consistent with the world data. Record values of resonance energies were obtained for highly excited states of 7He (24.5 MeV) and 9He (10.5 MeV).

On behalf of BSTU-PhIAN-INF collaboration

Possible temporal variations of nucleus decay parameters were studied extensively in the last years, their observation can be the signal of unknown physical effects. Several experiments reported the annual and daily decay rate oscillations in alpha and beta-decays of some radioactive nuclides at the level of .05 % [1,2]. Also, correlation of Mn-54 e-capture decay rate with electromagnetic solar activity was reported [1]. BSTU - PhIAN - INF collaboration studies decay rate variations in
Co-60 β-decay and Fe-55 inverse β-decay (e-capture) isotopes. 1.3 Mev γ-quanta which accompanies Co-60 beta-decay were detected by cooled germanium semiconductor spectrometer. Fe-55 e-capture accompanied by X-ray with energy 5,9 or 6,4 KeV which in our set-up detected by cooled Si-Pin detector. Measurements of decay rate performed in 2016 -2021 , demonstrate that together with observed Fe-55 decay exponent with life-time 1004 days, oscillation period 29.5 +/- 1.5 days corresponding to moon month is found with amplitude (.22 +/- .04)% ; theoretical model of such decay rate deviations considered in [3,4].
Possible influence of electromagnetic solar activity was studied during 2015 – 2022 for Fe-55 decay rate, simultaneously with C0-60 decay rate in Novosibirsk INF at the distance 2800 km from Moscow [5]. The deviations of similar form and size from exponential decay low at the average level (.55 +/-.004)% were detected in both experiments during October- December 2018. Supposedly, they can be related to solar activity minimum started in the beginning of 2018 and continued till the end of 2020. In addition, ten decay rate dips of the order 1 % with duration from 50 to 208 hours were found. It is shown that such dips occur 48 – 80 hours before X-ray solar flare events with significant reliability, existence of such correlations can have important practical applications [5]. SOLARIS project plans to perform simultaneous measurements of Fe-55, Co-60 decay parameters at
International Space Station and Earth labs. to study their correlations with electromagnetic solar activity, in particular, with X-ray solar flare events .

1. E. Fischbach et al. , Rev. Space Sci. 145, 285 (2009); Astrop. Phys. 59,47 (2014)

2. E. Alekseev et al. , Phys. Part. Nucl. 47, 1803 (2016); ibid. 49, 557 (2018)

3. S. Mayburov Int. J. Theor. Phys. 60, 630 (2021)

4. S. Mayburov Phys. Part. Nucl. 51, 458 (2020)

5. S. Bogachev et al. J. Phys.: Conf. Series 1690, 012028-012035 (2020)

Cluster structure plays an important role in nuclei, in particular, in light ones. One of the common types of clusters is the α-particle. Consisting of four nucleons, the alpha particle is tightly bound and has no excited state up to 20 MeV and behaves as a well-established subunit in nuclei.

Considerable attention has been drawn to the studies of $\alpha$-cluster states in $^{12}$C, especially the second 0$^+$ state, located at E$_x$ = 7.65 MeV, which is 0.38 MeV above the 3$\alpha$ threshold. This state was named Hoyle state by name of the astrophysicist who predicted it. It plays an extremely important role in nucleosynthesis. The properties of the Hoyle state in $^{12}$C determine the ratio of carbon to oxygen formed in the stellar helium burning process that strongly affects the future evolution of stars. A detailed analysis of the structure of $^{12}$C with the microscopic 3$\alpha$ cluster model was made about 30 years ago. The 3$\alpha$ generator coordinate method (GCM) and 3$\alpha$ resonating group method (RGM) calculations showed that the Hoyle state in $^{12}$C has a loosely coupled 3$\alpha$ structure and an enlarged radius. Modern microscopic calculations in the framework of cluster models such as the antisymmetrized molecular dynamics (AMD) and the fermionic molecular dynamics (FMD) also predict an increased radius of this above-threshold cluster state. Within $\alpha$-particle Bose-Einstein condensation ($\alpha$BEC) model the Hoyle state is considered to be the simplest example of the $\alpha$-condensed state with increased radius.

A question naturally arises: do analogs of the Hoyle state exist in more massive 4N nuclei. First possible candidate is the $^{16}$O. $\alpha$BEC model predicted that 0$^+$ states, particularly the 4th or the 6th, can be possible analogs of the Hoyle state and have $\alpha$-condensed structure. Our analysis within Modified diffraction model has shown that 0$^+_2$-0$^+_6$ states have normal non-increased radii.

The next goal is $^{20}$Ne. The root mean square radii of $^{20}$Ne in the short-lived excited states were estimated for the first time from the analysis of $\alpha$ + $^{20}$Ne diffraction scattering. Differential cross sections of the elastic and inelastic $\alpha$ + $^{20}$Ne scattering in the incident energy range from a few MeV/nucleon up to 100 MeV/nucleon were analyzed by the modified diffraction model. No significant radius enhancement for the members of K$^\pi$ = 0$^+_1$ and K$^\pi$ = 2$^−$ bands in comparison with the ground state was observed. At the same time 20$\%$ radius enhancement was obtained for the K$^\pi$ = 0$^−_1$ band members. Moreover, for the 0$^+_2$ state located above $\alpha$-emission threshold increased radius was observed. This result can speak in favor of possible $\alpha$-condensate structure of the 0$^+_2$ state and can be considered as a possible analog of the famous 7.65-MeV 0$^+_2$ Hoyle state of $^{12}$C.

The mass distributions of 252Cf(sf) ternary fission fragments with the emission of a light charged particle are measured. The experiment was carried out on a modernized COMETA time-of-flight spectrometer consisting of 28 silicon pin diodes with a thin input window and a starting detector based on microchannel plates. The threshold for the measured particle energy was ~1 MeV. The mass resolution for alpha particles was ~0.34 amu. It was found for the first time that in fission events with alpha particles emitted at an angle close to 90° to the fission axis, a fragment passing through the emitting foil of the starting detector loses mass up to 16 amu. decay [1-4].
Yu.V. Pyatkov et al., Eur. Phys. J. A. 45, 29 (2010).
Yu.V. Pyatkov et al., Eur. Phys. J. A. 48, 94 (2012).
D.V. Kamanin and Yu.V. Pyatkov, Clusters in Nuclei, Lecture Notes in Physics. 875, 183 (2013).
Yu.V. Pyatkov et al., Phys. Rev. C. 96, 064606 (2017).

The BECQUEREL experiment is aimed at solving topical problems in nuclear clustering physics [1]. The used method of nuclear track emulsion (NTE) makes it possible, due to its unique sensitivity and spatial resolution, to study by means of the unified approach multiple final states arising in dissociation of relativistic nuclei. Currently, the research has been focused on the theoretical concept of α-particle Bose- Einstein condensate (αBEC) – the ultra cold state of several S-wave α-particles near coupling thresholds. The unstable 8Be nucleus is described as 2αBEC, and the 12C(0+2) excitation or Hoyle state (HS) as 3αBEC. Decays 8Be → 2α and 12C(0+2) → 8Beα can serve as signatures for more complex αBEC decays. Thus, the 0+6 state of the 16O nucleus at 660 keV above the 4α threshold, considered as 4αBEC, can sequentially decay 16O(0+6) → α12C(0+2) or 16O(0+6) → 28Be(0+). Confirmation of the existence of this and more complex forms of αBEC could provide the basis to expand scenarios for the synthesis of medium and heavy nuclei in nuclear astrophysics.
The consideration of αBEC as an invariant phenomenon indicates an opportunity of its search in the relativistic fragmentation. A practical alternative is provided by NTE layers longitudinally exposed to relativistic nuclei. In them, the invariant mass of ensembles of He and H fragments can be determined from emission angles in the approximation of conservation of momentum per nucleon of a parent nucleus. Due to extremely small energies and widths, the 8Be and HS decays, as well as 9B → 8Bep, are identified in light nucleus fragmentation by an upper constraint on the invariant mass [2].
Having been tested, this approach has been used to identify 8Be and HS and search for more complex states of αBEC in fragmentation of medium and heavy nuclei. Recently, based on the statistics of dozens of 8Be decays, we have found more probability of detecting 8Be in the event with increasing the number of relativistic α-particles. It has been concluded that contributions of 9B and HS decays also grow [3]. The exotically large sizes and lifetimes of 8Be and HS allow us to assume an opportunity of synthesizing αBEC by successively connecting the emerging α-particles 2α → 8Be, 8Beα → 12C(0+2), 12C(0+2)α → 16O(0+6), 28Be → 16O(0+6) and further, with a decreasing probability at each step, when γ-quanta or recoil particles are emitted. The main task of the forthcoming stage of the project is to clarify the relation between the appearance of 8Be and HS and α-ensemble multiplicities and on this basis search for decays of the 16O(0+6) state. In this regard, the purpose is to measure multiple channels of 84Kr fragmentation below 1 GeV per nucleon. There is a sufficient number of NTE layers, whose transverse scanning by means of the motorized microscope Olympus BX63 makes it possible to achieve the required statistics. A status of the searches is overviewed.

[1] P.I. Zarubin, Lect. Notes in Phys. 875, Clusters in Nuclei, Volume 3. Springer Int. Publ., 51 (2013); arXiv: 1309.4881.
[2] D.A. Artemenkov et al., Eur. Phys. J. A 56 (2020) 250; arXiv: 2004.10277.
[3] A.A. Zaitsev et al., Phys. Lett. B 820 (2021) 136460; arXiv: 2102.09541.

An overview of GBAR experiment in CERN on antihydrogen gravitational mass measurement is given. The use of interference of gravitational quantum states of antihydrogen in the field of the Earth is discussed in view of precision measurement of gravitational mass of antihydrogen.

At the present state-of-the-art, the simplest inflationary models, based either on scalar fields in General Relativity or on modified f(R) gravity, which produce the best fit to all existing observational data, require only one dimensionless parameter taken from observations. These models include the pioneer R+R2 (Starobinsky) one, the Higgs model, and the mixed R2-Higgs model that has been shown to be effectively one-parameter, too. They predict scale-free and close to scale-invariant power spectra of primordial scalar perturbations and gravitational waves generated during inflation. Their target prediction for the tensor-to-scalar ratio is r=3(1 - ns)2 = 0.004. Still future observations, in particular discovery of primordial black holes, may prove that the primordial scalar power spectrum has additional local peaks and troughs what requires at least two new parameters. I discuss mechanisms to produce such features including the recently proposed one which arise in many-field inflation with a large non-minimal kinetic term of an inflaton field leaving inflation before its end [1]. In this case, in addition to PBHs, small-scale secondary gravitational waves with a non-scale-invariant power spectrum are generated, too. As for local non-scale-free features at cosmological scales, the present CMB data do not favor them, but are not able to exclude them completely [2].

1. M. Braglia, D. K. Hazra, F. Finelli, G. F. Smoot, L. Sriramkumar, A. A. Starobinsky. JCAP 2008, 001 (2020); arXiv:2005.02895.
2. D. K. Hazra, D. Paoletti, I. Debono, A. Shafieloo, G. F. Smoot, A. A. Starobinsky, JCAP 2112, 038 (2021); arXiv:2107.09460.

Recent data of JWST indicate to surprisingly rich population of the early universe at redshifts exceeding 15 by the well developed galaxies in strong contradiction with the conventional expectations. These picture was essentially predicted long ago by the the mechanism of massive and super massive PBH formation in the very early universe, which could seed galaxy formation.
According to this mechanism, our Galaxy may have quite noticeable amount of antimatter, in particular in the form of antistars, antinuclej, and positrons which is strongly indicated by the observation of the several last years.

According to the prescriptions of the conventional cosmological LCDM-model, first galaxies had to start their formation when hierarchically assembled dark halos reached 100 million solar masses. They are thought to be dwarf disk galaxies. In fact, the earliest galaxy is observed now at the redshift of z=11, about 0.5 Gyr after the Big Bang, and it is much more massive than a hypothetical first-generation galaxy in the theory. Perhaps, it is related to the method of searching for high-redshift galaxies due to a so called ‘astronomical selection’ effect. However, all we know now about the galaxies having lived during the first billion year of the Universe evolution can be attributed mostly to ‘Ly-break’ galaxies – those with the typical stellar mass of 10 billion solar masses, with the star formation rate of a few dozen solar mass per year, and nearly solar chemical composition. All the hopes to find more early galaxies at z>12 are now related to the James Webb Space Telescope which surveys the sky with an unprecedent high spatial resolution in the mid-infrared spectral range where the peak of galaxy luminosity is expected for objects at z>12.

In this talk I will review the presence of recently reported foregrounds in the cosmic microwave background (CMB) radiation associated with extended regions surrounding nearby galaxies. Using the cross correlation of Planck and WMAP maps and the 2MRS galaxy catalogue it is found that the mean temperature radial profiles around nearby galaxies at $ cz\le 4500$ km s$^{−1}$ show a statistically significant systematic decrease of $\sim15 \mu$K extending up to several degrees. This effect strongly depends on the galaxy morphological type and is significantly stronger for the largest (luminous) late-type galaxies. Our results show that the presence of these statistically relevant foregrounds in the CMB maps should be considered in detailed cosmological studies and current CMB anomalies analysis.

Due to an expected progress of observational facilities Zakharov et al. (2005a) proposed to use global and ground – space VLBI observations in mm band to detect a shadow at Sgr A$^*$ as a tool to evaluate a black hole spin and a position angle of distant observer. In particular, it was predicted that the shadow diameter is around 52 μas for the Sgr A$^*$ case and this prediction was remarkably confirmed by the Event Horizon Telescope (EHT) Collaboration on 12 May 2022. Also Zakharov et al. (2005b) showed that a black hole charge can be evaluated from shadow size estimates. Zakharov (2014) generalized these relations for the tidal charge case. In 2019 the EHT Collaboration reconstructed shadows at M87$^*$ in 2019 and at Sgr A$^*$ in 2022. As it was shown by Zakharov (2022) a black hole charge can be found analytically from these observations.

References

Zakharov A. F. et al., New Astronomy 10, 479 (2005a)

Zakharov A. F. et al., A & A 442, 795 (2005b)

Zakharov A. F. , PRD 90, 062007 (2014)

Zakharov A. F. , Universe 8, 141 (2022)

We use the sizes of dark spots at the EHT images of supermassive black holes M87 and SgrA for inferring their spins, a>0.75 and a=0.65-0.9, respectively. It is supposed that black spots at the EHH images of M87 and SgrA are the lensed images of their event horizon globes. We reconstruct the form of lensed event horizon by using numerical calculations of the photon trajectories in the Kerr metric. Bright rings embracing the dark spots at the EHH images of M87 and SgrA, seemingly, related with the very luminous accreting matter. These accreting matter, as by product, illuminates the event horizon outskirts providing the dark spots at the black hole images. The lensed images of event horizons (related with photons emitted to the distant observer inside the photon spheres) are always projected at the celestial sphere inside the awaited position of the classical black hole shadows, which are invisible in both cases of M87 and SgrA.

We consider the generalized Tolman solution of general relativity, describing the evolution of a spherical dust cloud in the presence of an external electric or magnetic field. In such models, we study the possible existence of wormhole throats defined as spheres of minimum radius at a fixed time instant, and prove the existence of throats in the elliptic branch under certain conditions imposed on the arbitrary functions that are present in the solution. It is further shown that
such dust clouds with throats can be inscribed into closed isotropic cosmological models filled with dust to form wormholes which exist for a finite period of time and experience expansion and contraction together with the corresponding cosmology. Explicit examples and numerical estimates are presented.

Nonstationary configurations of a massless spherically symmetric scalar field are considered. We use an approach to the construction of nonstationary gravitating configurations of a scalar field, which makes it possible to reduce the Einstein-scalar field system to a single equation written in invariant quantities. New exact and numerical nonstationary solutions for a massless scalar field are obtained. These solutions are associated with characteristic functions of a special form. It is shown that there are no asymptotically flat solutions for the considered classes of characteristic functions.

We perform canonical analysis of an action in which 2+1-dimensional gravity with negative cosmological constant is coupled to
cylindrically symmetric dust shell. The resulting phase space is finite dimensional having geometry of SO(2,2) group manifold.
Replacing the Poisson brackets by commutators results in the algebra of observables which is a quantum double D(SL(2)_q).
Deformation parameter q is real when the total energy of the system is below the threshold of a black hole formation, and a root of
unity when it is above. Inside the black hole the spectra of the shell radius and time operator are discrerte and take on a
finite set of values. Transition amplitudes between these states are everywhere finite, including the central singularity.

In the last two decades, a number of observed flares in inactive galaxies have been associated with the tidal disruption of stars by strongly gravitating objects located in the centers of galaxies. Tidal disruption events provide us with a new channel for exploring the central compact objects. In this report, we compare tidal forces and some features of tidal disruption in the vicinities of supermassive black holes and naked singularities surrounded by dark matter. These objects are considered in an idealized static Einstein-Klein-Gordon model consisting of a pointlike massive body in the center of spherically symmetric, asymptotically flat configuration of a self-gravitating scalar field. Varying the mass and the scalar field distribution (or, equivalently, the nonlinear self-interaction potential), we can obtain any physically reasonable radial density distribution of dark matter. It turns out that the tidal effects for vacuum black holes and black holes with scalar hair are differ essentially from those for naked singularities with scalar hair.

We consider a family of 4-dimensional black hole solutions
governed by natural number $q= 1, 2, 3 , \dots$, which appear in the model
with anisotropic fluid and the equations of state: $p_r = -\rho (2q-1)^{-1}$,
$p_t = - p_r$, where $p_r$ and $p_t$ are pressures in radial and transverse
directions, respectively, and $\rho > 0$ is the density. These equations of state obey weak, strong and dominant energy conditions. For $q = 1$ the metric of the solution coincides with that of the Reissner-Nordstr\"om one. The global structure of solutions is outlined, giving rise to Carter-Penrose diagram of Reissner-Nordstr\"om or Schwarzschild types for odd $q = 2k + 1$ or even $q = 2k$, respectively. Certain physical parameters corresponding to BH solutions
(gravitational mass, PPN parameters, Hawking temperature and entropy)
are calculated. We obtain and analyse the quasinormal modes for a test massless scalar field in the eikonal approximation. For limiting case $q = + \infty$, they coincide with the well-known results for the Schwarzschild solution. We show that the Hod conjecture which connect the Hawking temperature and the damping rate is obeyed for all $q \geq 2$ and all (allowed) values of parameters.

We demonstrate the possibility of purely gravitational production of primordial black holes in multidimensional $f(R)$-gravity. Our model is based on a compact extra space whose size is stabilized by quadratic corrections to the Ricci scalar in multidimensional Lagrangian. Such a Lagrangian gives rise to a low-energy model containing an effective scalar field capable for the domain walls production. Formed during inflation, these domain walls are dense enough so they collapse into primordial black holes soon after inflation ends. The proposed mechanism for the formation of primordial black holes does not require any matter fields.

Recent results on $B_c$ production and decays from the proton-proton collision data taken by the ATLAS experiment will be presented.
The measurement of the differential ratios of $B_c^+$ and $B^+$ production cross sections at 8 TeV will be shown.
New results on the $B_c$ decays to $J/\psi$ $D_s(*)$ final states obtained with the Run 2 data at 13 TeV will also be reported.

The first measurements of the transverse momentum
($p_{\rm{T}}$) spectra, integrated yields and mean $p_{\rm T}$ of $\Sigma^{0}$ and $\overline{\Sigma}^{0}$ hyperons
in pp collisions at $\sqrt{s} = 7$ TeV at the LHC are presented.
The $\Sigma^{0}$($\overline{\Sigma}^{0}$) is reconstructed
via its electromagnetic decay channel $\Lambda$($\overline{\Lambda}$)$\gamma$.
The $\Lambda$ ($\overline{\Lambda}$) baryon is reconstructed via its decay into p + $\pi^{-}$
($\overline{ \rm{p}} + \pi^{+}$), while the photon is detected by exploiting the unique capability
of the ALICE detector to measure low-energy photons via conversion into e$^{+}$e$^{-}$ pairs
in the detector material.
The yield of $\Sigma^{0}$ is compared to that of the $\Lambda$ baryon, which has the same quark
content but different isospin. These data contribute to the understanding of hadron production
mechanisms and provide a reference for constraining QCD-inspired models and tuning Monte Carlo
event generators such as PYTHIA.

In addition, the results on the first detection of $\Sigma^{+}$ hyperon at LHC with ALICE are shown.
Also, the feasibility of a search for a bound state of proton, neutron and
$\Sigma^{0}(\Sigma^0$-hypernuclei $^{3}_{\Sigma^{0}}$H) is presented, based on the luminosities foreseen for
the LHC Runs 3 and 4.

A method which can distinguish quark and gluon jets in mixed sample was described in report. The tagger is a likelihood discriminant constructed out of three variables: particle multiplicity, minor axis of the jets profile ellipse and fragmentation function. This quark-gluon likelihood (QGL) discriminator is used in analyses carried out in the CMS experiment. Using QGL discriminator, a method for measuring the fraction of gluon jets in mixed sample was developed. Mathematical aspects of QGL discriminator and method to measure gluon fraction are described.

The NA65 (DsTau) experiment at CERN-SPS is studying tau-neutrino production process in proton-nucleus interaction and aims to improve significantly an accuracy of calculations of tau neutrino fluxes for  accelerator based neutrino experiments. For detecting short lived particles (especially decaying via tau neutrino), the experiment uses a setup based on high resolution nuclear emulsions, that are fully automatically scanned after the irradiation. Although the detector registers tracks with unprecedented density of $10^5 – 10^6$ tracks/$cm^2$, the ultimate spatial and angular resolution of the emulsions allows a successful events reconstruction. The first results of the data analysis of the pilot run will be reported.

An overview of the latest results from Kaon experiments at CERN and the future prospect will be presented. The NA62 experiment collected the world's largest dataset of charged kaon decays in 2016-2018, leading to the first measurement of the branching ratio of the ultra-rare $K^+ \to \pi^+ \nu \bar\nu$ decay, based on 20 candidates.
The radiative kaon decay $K^+ \to \pi^0 e^+ \nu \gamma$ ($Ke3\gamma$) is studied with the data recorded in 2017-2018, achieving the most precise measurements of the $Ke3\gamma$ branching ratio and T-asymmetry.
Preliminary results from an analysis of the flavour-changing neutral current $K^+ \to \pi^+ \mu^+ \mu^-$ decay led to the most precise determination of the form-factor parameters $𝑎+$ and $𝑏+$ using data collected in 2017-2018.
New preliminary results are obtained from an analysis of the $K^+ \to \pi^+ \gamma \gamma$ decay using data collected in 2016-2018 with a minimum-bias trigger, leading to an unprecedented sensitivity. This analysis can be naturally
extended to search for the $K^+ \to \pi^+A$, $A \to \gamma\gamma$ process, where $A$ is a short-lived axion-like particle.
The NA62 dataset is exploited to search for light feebly interacting particles (heavy neutral leptons) in Kaon decays. Dedicated trigger lines are employed to collect di-lepton final states, which allowed establishing new stringent upper limits on the rates of lepton flavour and lepton number violating kaon decays.
NA62 can also be run as a beam-dump experiment, by removing the Kaon production target and moving the upstream collimators into a "closed" position. Analyses of the data taken in beam-dump mode are performed to search for visible decays of exotic mediators, with a particular emphasis on Dark Photon Models.
The first observation of the decay $K^{\pm} \to \pi^0 \pi^0 \mu^{\pm} \nu$ ($K00\mu4$) by the NA48/2 experiment at CERN and the preliminary measurement of the branching ratio are also presented. The result is converted into the first
measurement of the $R$ form factor in $Kl4$ decays and compared with the Chiral Perturbation Theory 1-loop
predictions.

Standard Model of high energy physics is very successful, but neutrino sector is not completely accommodated into it (e.g. neutrino oscillations). One of the possible solution is introduction of heavy sterile neutrino, which does not have any flavour and interacts with only flavour SM neutrinos via oscillations.

In this talk we present the preparatory studies dedicated to the future search heavy sterile neutrino N in CMS Experiment, where N is originating from Ds+ —> mu+ N —> mu+ mu+ pi- decay, and Ds+ are coming from semi-leptonic decays Bs0 —> Ds+ mu- mu_nu. These studies are original and were conducted for the first time within the CMS Experiment.

The talk is divided into the two parts.
For the first one we study the reference and normalisation channels Ds+ —> phi pi+ —> K+ K- pi+ and Ds+ —> pi+ pi- pi+ (where Ds+ is coming from both prompt and semi-leptonic Bs0), using CMS data (2018 sqrt(s) = 13 TeV pp-collisions) with the dedicated BParking dataset (which contains a detached muon with large p_T — semi-leptonic signature).
For the second one we provide the detailed studies of signal Ds+ —> mu+ N decay using Monte-Carlo simulation samples with CMS detector 2018 conditions. Several points on (m_N, V_Nmu) plane are generated for the sterile neutrino properties, where m_N and V_Nmu are the expected mass of N and coupling parameter with mass. We study kinematic and topological variables of the involved particles, generator and reconstruction efficiencies in dependence of N properties.

The obtained results will be used for the future search for this decay and heavy sterile neutrino, using real CMS Experiment data.

The first observation of the decay K± → π
0π
0µ
±ν (K00
µ4) by the NA48/2
experiment at the CERN-SPS is reported. From 2437 selected signal candidates with 15%
background contamination, the branching ratio of the decay is measured in the restricted
kinematical space of the squared dilepton mass above 0.03 GeV2
/c4
and extrapolated to the full
kinematical space. The result is found to be in agreement with the R form factor from 1-loop
Chiral Perturbation Theory.

A new precise measurement of the vector and axial-vector form factors difference $F_V-F_A$ in the decay $K^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma}$ is presented. About 145K events of $K^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma}$ have been selected in OKA experiment. The result is $F_V-F_A=0.135\pm0.017(stat)\pm0.024(syst)$. The number of events is about 1.5 times higher and both errors are smaller than last published OKA result. The presented result is considered as preliminary.

The K+ ==> pi0 mu+ nu gamma (Km3g) decay has been measured
with OKA setup at the RF-separated 17.7 GeV/c momentum kaon beam
of the U-70 accelerater. The data was collected in two run in 2012-2013 yrs.
and corresponds to the flux of 2.62e+10 "live" kaons entering the decay volume.
More than 900 signal events were found in the "standard" Particle Data
Group (PDG) region of 30-60 MeV energy of the emitted photon in the rest frame
of the decaing kaon. Using 4.48e+06 events sample of normalization decay
K+ ==> pi0 mu+ nu (Km3), the branching ratio B(km3g)/B(km3) was found to be
(4.49+/-0.37(stat))e-4. This value can be transformed (PDG B(km3)=3.352%)
to B(km3g)=(1.51+/-0.12(stat))e-5.
Our results are preliminary, with systematic errors are being estimated.

We present new soliton solutions in a class of four-dimensional supergravity theories. For special values of the parameters, the solutions can be embedded in the gauged maximal N=8 theory and uplifted in the higher-dimensional D=11 theory. We also find BPS soliton configurations, preserving a certain fraction of supersymmetry.

Solitons play a special role in classical physics as well as in quantum and string theory, determining a richer structure of the full non-perturbative regime. This different class of exact solutions can be obtained from a double Wick rotation of a former black hole configuration, the new solutions characterizing a regular spacetime configuration devoid of horizons.
In non-supersymmetric AdS gravity, solitons play a fundamental role as they can be treated as ground states for suitable field theories. The negative mass of the AdS soliton has a natural interpretation as the Casimir energy of a gauge theory living on the conformal boundary. In a non-susy version of the AdS/CFT conjecture, this would indicate that the soliton is the lowest energy solution with the chosen boundary conditions, leading to a new kind of positive energy conjecture.

Finally, BPS gravitational solitons preserving a certain fraction of supersymmetry can be found, providing a privileged framework in studying the system evolution: the resulting dynamical equations are in fact typically first-order, as compared to the standard second order equations of motion.

It has been shown that non-Abelian vortex string supported in four dimensional (4D) ${\mathcal N}=2$ supersymmetric QCD (SQCD) with the U(2) gauge group and $N_f = 4$ quark flavors becomes a critical superstring. This string propagates in the ten dimensional space formed by a product of the flat 4D space and an internal space given by a Calabi-Yau non-compact threefold, namely, the conifold. The spectrum of closed string states of the associated string theory was obtained using the equivalence between the critical string on the conifold and the non-critical string on the semi-infinite cigar described by SL($2, \mathbb{R}$)/U(1) Wess-Zumino-Novikov-Witten model. This spectrum was identified with the spectrum of hadrons in 4D ${\mathcal N}=2$ SQCD.
In order to describe effective interactions of these 4D hadrons in this paper we study correlation functions of normalizable vertex operators localized near the tip of the SL($2, \mathbb{R}$)/U(1) cigar. We also compare our solitonic string approach to the gauge-string duality to the AdS/CFT-type holography for little string theories (LSTs). The latter relates off mass-shell correlation functions on the field theory side to correlation functions of non-normalizable vertex operators on the cigar. We show that in most channels holographic approach works in our theory because normalizable and non-normalizable vertex operators with the same conformal dimension are related due to the reflection from the tip of the cigar. However, we find that holography does not work for lightest hadrons with given baryonic charge.

Monopole condensation causes color confinement and instantons induce chiral symmetry breaking. Color confinement and chiral symmetry breaking are closely tied to one another through monopoles and instantons in the QCD vacuum. However, it is difficult to reveal the quantitative relations and effects among monopoles, instantons, color confinement, and chiral symmetry breaking by perturbative calculations because of the strong interaction in the low-energy region of the QCD. Therefore, we perform simulations of lattice gauge theory and investigate the impacts of the monopole and instanton creations on color confinement and chiral symmetry breaking.

In our research, we apply the monopole creation operator to the vacuum and add the monopoles and anti-monopoles to the SU(3) gauge field configurations of the quenched approximation. We vary the magnetic charges of the monopole creation operator to increase the number of monopoles and anti-monopoles.

We then calculate the eigenvalues and eigenvectors of the overlap Dirac operator that preserves the exact chiral symmetry in lattice gauge theory, using the normal configurations and the configurations to which the monopoles and anti-monopoles are added. We count the number of instantons and anti-instantons that are created by the additional monopoles and anti-monopoles. Finally, we investigate the impacts induced by monopole and instanton creations on observables that experiments can detect.

We have found the catalytic effect in which the lifetime of the charged pion becomes shorter than the experimental result by increasing the number density of the instantons and anti-instantons [1]. To my knowledge, no one has mentioned this effect before. We have demonstrated that the finite lattice volume and the discretization do not affect the outcomes that we obtained [2].

In my presentation, I would like to talk about the catalytic effect.

References

[1] M. Hasegawa, Monopole and instanton effects in QCD, JHEP 09 (2020) 113, [arXiv: 1807.04808].

[2] M. Hasegawa, Color confinement, chiral symmetry breaking, and catalytic effect induced by monopole and instanton creations, accepted by the EPJC on the 7th of October 2022, [arXiv: 2203.11357].

We consider oscillons - localized, quasiperiodic, and extremely long-living classical solutions in models with real scalar fields. We develop their effective description in the limit of large size at finite field strength. Namely, we note that nonlinear long-range field configurations can be described by an effective complex field $\psi(t,\mathbf{x})$ which is related to the original fields by a canonical transformation. The action for $\psi$ has the form of a systematic gradient expansion. At every order of the expansion, such an effective theory has a global U(1) symmetry and hence a family of stationary nontopological solitons - oscillons. The decay of the latter objects is a nonperturbative process from the viewpoint of the effective theory. Our approach gives an intuitive understanding of oscillons in full nonlinearity and explains their longevity. Importantly, it also provides reliable selection criteria for models with long-lived oscillons. This technique is more precise in the nonrelativistic limit, in the notable cases of nonlinear, extremely long-lived, and large objects, and also in lower spatial dimensions. We test the effective theory by performing explicit numerical simulations of a $(d+1)$-dimensional scalar field with a plateau potential.

The Landau-Khalatnikov-Fradkin (LKF) transformation is a powerful and elegant transformation allowing to study the gauge dependence of the propagator of charged particles interacting with gauge fields. With the help of this transformation, we derive a non-perturbative identity between massless propagators in two different gauges. From this identity, we find that the corresponding perturbative series can be exactly expressed in terms of a hatted transcendental basis that eliminates all even Euler zeta-functions. This explains the mystery of even zeta-values observed in multi-loop calculations of Euclidean massless correlators for almost three decades now. Our construction further allows us to derive an exact formula relating hatted and standard zeta-functions to all orders of perturbation theory.

A normalizable static supersymmetric bound ground state annihilated by the super-generators has got zero number of internal nodes in the framework of one-dimensional supersymmetric quantum mechanics. The super-generator transformations between excited super-partner bound states as combined with the standard technique of wronskian provides an elegant and self sufficient way to derive the equality of internal nodes amount to the number of consequent excitation.

In this work we explore the nonpertorbative corrections, especcialy operator dimension which is connected to existing of short strings, basing on our method: processing of experimental data on $e^+e^-$-annihilation into even number of pions (BaBar, CMD-2, OLYA) by constructing the Adler function in two ways (through dispersion representation and through the OPE series), applying the Borel transform, compiling the sum rule, and extracting of nonperturbative corrections.
​
Another task, we check the range of values which coefficient dimension 6, $С_6$, can take, considering the hypothesis of vacuum dominance, and a possibility of other intermediate states, contributing to four-quark condensate included in $С_6$.
​
How other nonperturbative corrections ($C_2$ and $C_4$ or gluon condensate)​ change when the additional contribution of intermediate states is taken into account?
It is shown that values of quark condensate that are not more than 1.2 times higher than the average obtained value, which corresponds to the available data, but not 2 or 1.5 times, are acceptable.
In this case, $C_4$ takes values close to the previously known​ ones, while $C_2$ is compatible to zero or negative.

The radiation of photons by electrons is investigated in the framework of quantum electrodynamics up to the second order in the coupling constant e. The N-particle, coherent, and thermal initial states are considered and the forms of the electron wave packets are taken into account. The explicit expressions for the intensity of radiation and the inclusive probability to record a photon are obtained. It is found that there are three processes in this order of perturbation theory where the electron wave packet radiates coherently and can be regarded as a charged fluid [1,2,3] even on integrating over the final states of the electron, i.e., in considering the inclusive probabilities and intensity of radiation. These processes are stimulated radiation by an electron, coherent radiation from a beam of particles, and reradiation of a photon in the Compton process [4]. We obtain the explicit expressions for the intensity of radiation and the inclusive probability to record a photon for these processes. As particular cases, we consider: stimulated transition radiation produced by an electron wave packet traversing a mirror [3] and backlighted by a laser wave, reradiation of photons in a coherent state by an electron wave packet. In the latter case, we deduce that the wave packet of a single electron can be endowed with the susceptibility tensor and this tensor has the same form as for an electron plasma in the small recoil limit.

References

1. I.P. Ivanov, D.V. Karlovets, Detecting transition radiation from a magnetic moment. Phys. Rev. Lett. 110, 264801 (2013)
2. I.P. Ivanov, D.V. Karlovets, Polarization radiation of vortex electrons with large orbital angular momentum. Phys. Rev. A 88, 043840 (2013)
3. Y. Pan, A. Gover, Spontaneous and stimulated emissions of a preformed quantum free-electron wave function. Phys. Rev. A 99, 052107 (2019)
4. P.O. Kazinski, G.Yu. Lazarenko, Transition radiation from a Dirac-particle wave packet traversing a mirror. Phys. Rev. A 103, 012216 (2021)
5. Y. Pan, A. Gover, Beyond Fermi’s golden rule in free-electron quantum electrodynamics: acceleration/radiation correspondence. New J. Phys. 23, 063070 (2021)

Using a nonperturbative approach based on the Cornwall-Jackiw-Tomboulis effective action Γ(S) for composite operators (S is the full fermion propagator), the phase structure of the (2 + 1)-dimensional Gross-Neveu (GN) and Thirring models is investigated. We have calculated Γ(S) and its stationary (or Dyson-Schwinger) equation for GN model and have shown that it has three different solutions for fermion propagator S corresponding to possible dynamical appearance of three different mass terms in the model. One is a Hermitian, but two others are non-Hermitian and PT even or odd. It means that two phases with spontaneous non-Hermiticity can be emerged in the system. Moreover, mass spectrum of quasiparticles is real in these non-Hermitian and PT even/odd phases.
Also the (2+1)-dimensional generalized Thirring model has been investigated by the Hartree-Fock method. The Lagrangian of this model is constructed from two different four-fermion structures, one of them takes into account the vector×vector channel with coupling constant Gv, the other - the scalar×scalar channel with coupling Gs. At some relation between bare couplings Gs and Gv dynamical generation of the Dirac and Haldane fermion masses is possible. As a result, phase portrait of the model consists of two nontrivial phases. In the first one the chiral symmetry is spontaneously broken due to dynamical appearing of the Dirac mass term, while in the second phase a spontaneous breaking of the spatial parity P is induced by Haldane mass term. It is shown that in the particular case of pure Thirring model, i.e. at Gs=0, the ground state of the system is indeed a mixture of these phases. Moreover, it was found that dynamical generation of fermion masses is possible for any finite number of Fermi-fields.
These methods could be interesting in studies of phase structure of different theories including QCD.

Based on
Phys.Rev.D 106 (2022) 8, 085002
Phys.Rev.D 105 (2022) 2, 025014
Int.J.Mod.Phys.A 36 (2021) 31n32, 2150231
Composite operator approach to

Measurements of the neutron cross-sections of heavy nuclei and their
analysis at the IAE and ITEP, carried out in the 1950s and later, made
it possible to find out deviations from the statistical model in the
distributions of positions and spacings of neutron resonance levels.
This work is a review of the analysis of the energies
of nuclear states and the particle mass spectrum, based on the
distinguished role of the electron, its symmetry, and radiative
correction.
A symmetry motivated approach to the problem of the particle mass
spectrum is due to the fact that the electron and nucleons add up
to the visible mass of the Universe, and the ratio of their masses
is very accurately estimated in the CODATA review as
$m_n/m_e=1838.6836605(11)$.
The representation of the nucleon masses in terms of the electron mass
and the period $16m_e=\delta$ allows checking the same
representation in the discreteness effect in the
energies of nuclear states and the masses of other particles.
The values of the pion parameters $f_\pi=130$\,MeV, $m_\pi=140$\,MeV
and $\Delta M_\Delta=147$\,MeV, as well as the parameters of the
Constituent Quark Model $M_q=3\Delta M_\Delta=441$\,MeV
and $M^\omega_q=3f_\pi=391$\,MeV contain a general empirical
discreteness parameter - the period $\delta$.

1. Sukhoruchkin S.I. et al. Proc. ISINN-28. JINR E3-2021, P. 234, 247, 259.
2. Sukhoruchkin S.I. Nucl. Part. Phys. Proc. 2021. V. 312 - 317. P. 185.
3. Sukhoruchkin S.I. Nucl. Part. Phys. Proc. 2022. V. 318 - 323. P. 191.

One of the most interesting properties of an atomic nucleus is its root-mean-square charge radius. This quantity can be measured using several different types of experiments. One of them is the observation of an isotopic shift in atomic spectra. An important feature of this method is the ability to determine the radii of short-lived nuclei. To find the radius from experimental data for one transition, mass and field shift constants turn out to be necessary. We have developed a new approach and calculated these constants for a number of the gold atom isotopes. An important feature of the calculations was a detailed analysis of the theoretical uncertainties. It was demonstrated that the use of modern methods for calculating the electronic structure makes it possible to achieve a high accuracy for the gold atom under consideration surpassing accuracy previous studies.
The present calculations have been supported by the Russian Science Foundation Grant 19-72-10019.

Generation of 14C radioisotope in the Earth atmosphere occurs by the 14N(n,p)14C reaction under cosmogenic fluxes and this process is considered as the main source of radiocarbon creation with rate of accumulation is evaluated as ~ 6.6 kg per year. An exclusively opportunities of dating based on the analysis of 14C concentration in the very old and ancient organic samples led to the discovery of short-term secular variation of radiocarbon in tree rings [1] and to the hypothesis of 14C generation under thunderstorms flashes.

The nature of the lightning phenomena in fact is connected with the development of electron avalanche in the strong atmospheric electric fields (about 300 kV/m and even up to 1000 kV/m) [2]. The very fast electron avalanche growth in the cloud electric fields ensures the phenomenon of terrestrial gamma-ray bursts [2,3]. These energetic gamma-rays generate the photonuclear reactions on atmospheric isotopes (with significant yield for hard photons of energy Eg up to 60 MeV) as 14N(g,n)13N, 16O(gamma,n)15O, 40Ar(gamma,n)39Ar.

An increase of neutron flux causes the next series of (n,gamma), (n,a), (n,p)-reaction and the 14N(n,p)14C is the top important for dating problem. For evaluating of the radiocarbon generation under thunderstorm conditions (and creation of another atmospheric isotopes too) it was proposed the model (realized in the spherical-layer geometry). The calculation were made at the several altitudes of the lower part of the atmosphere at the altitudes from 250 m up to ~15 km (that allows to cover the possible heights of detected lighting) [4].

Decrease of the atmospheric densities at increase of the altitude is critical for electron avalanche evolution and is included in the model. It was obtained the yield of C14 from thunder discharges evaluated as 0.0001 % relative to cosmogenic one. The results support the hypothesis that radiocarbon rise in the old tree rings (at AD 774–775) [1] can be explained by increased Sun activity of the Sun at this time interval.

1. F. Miyake, K. Nagaya, K. Masuda, T. Nakamura, Nature 486, (2012) 240. doi.org/10.1038/nature11123

2. Joseph R. Dwyer · David M. Smith · Steven A. Cummer. High-Energy Atmospheric Physics: Terrestrial Gamma-Ray Flashes and Related Phenomena. Space Sci Rev (2012) 173:133–196. DOI 10.1007/s11214-012-9894-0.

3. Leonid Babich, Thunderous nuclear reactions. Nature, v.551 (2017) 443. doi.org/10.1038/d41586-017-07266-w

4. V. I. Lyashuk, Evaluation of Radiocarbon 14C Yield Under Conditions of Thunderstorms, Geophysical Research Letters, 48, e2021GL095357. https://doi.org/10.1029/2021GL095357

Studies of hypernuclei with proton or neutron excess are of particular relevance now in strangeness physics. Such systems scarcely studied experimentally can currently be produced in heavy ion collisions at NICA complex developed in DUBNA. Research in exotic hypernuclei can provide insight into various aspects of hyperonic interactions including density dependence of the ΛN interaction, core polarization and charge symmetry breaking (CSB). Some of these features may have a profound influence on the structure of systems with an extreme excess of neutrons or protons, such as halo nuclei and neutron stars. Furthermore, considering the attractive nature of ΛN interaction, there is a chance to stabilize loosely bound nuclear systems and even get bound hypernuclei with unstable cores. Our goal was to study such occurrences for proton-rich hypernuclei up to $Z=20$.

We address the structure of Λ-hypernuclei in the framework of Hartree-Fock approach with effective potentials in the Skyrme form. This phenomenological approach allows us to analyze the hypernuclear properties in relation to both nucleon-nucleon and hyperon-nucleon components of the general baryonic interaction. The model is shown to reproduce the experimental hyperon binding energies $B_Λ$ in light hypernuclei, as well as predict the slower growth of $B_Λ$ in heavier hyperisotopes. In essence, this signifies that the glue-like role of the Λ-hyperon decreases with increasing $A$, and it is more likely to bind lighter unbound nuclei with Λ. We study the proton-rich isotopes up to calcium and draw conclusions on the possibility of the proton drip line shift due to Λ-hyperon on the hypernuclear chart in this region. We show hypernuclei $_Λ^9$C, $_Λ^{17}$F, $_Λ^{20}$Na and $_Λ^{20}$Mg to be the most promising candidates for hyperisotopes with unbound nucleon cores.

I.N. Borzov 1,2, S.V. Tolokonnikov1,3
1 National Research Centre “Kurchatov Institute”, Moscow, Russia
2Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, Dubna, Russia
3 Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
†E-mail: Borzov_IN@nrcki.ru, cc: ibor48@mail.ru

The equations of state for infinite, symmetric nuclear matter (SNM) and pure neutron matter (PNM) are analyzed in terms of the Fayans energy density functional. DF3-a functional [1] tuned via previously unused volume (isovector) parameter h-2. A quality of the previous global fit of the Fayans EDF [2] has been kept for the nuclear densities, masses of nuclei, single-particle levels and charge radii. Additional constraint is implemented from the upper bound of the giant dipole resonance energy in 208Pb. The symmetry energy slope at saturation density L(ρ0) is calculated with the relativistic corrections taken into account. Its values obtained for different h-2 (Fig.1) are compared to the ones derived from the extended set of restrictions. They were obtained in [3] making use of the data on nuclear masses, results of ab initio calculations with N3LO, ΔRnp values derived from PREXP-II, CREX experiments, as well as the latest data from the radii of neutron stars and registration of gravitational waves. As it can be seen (Fig.2), for newly tuned DF3-a functional, the SNM EOS is softer than the ones obtained from the FANDF0 functional [2], as well as from APR [4], AFDMC [5], N2LO(D2,E1) and N2LO(D2,Eτ) [6]
Supported by the grant of Russian Scientific Foundation (RSF 21-12-00061).

Fig.1. Density dependence of the L(ρ) for symmetric nuclear matter. Calculation with the new version of the DF3-a functional for various values of the h−2 parameter.
Fig. 2. Energy per nucleon for SNM as a function of density. Our calculation with the FaNDF0[1], new version of the DF3-a[2] as well as for APR [4], AFDMC [5], N2LO[6] functionals.

1. S.V. Tolokonnikov, E.E. Saperstein, Phys. At. Nucl. 74, 1277 (2011).
2. S.A. Fayans, JETP Lett. 68, 169 (1998).
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   Yrevan, Armenia, 2021.
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5. S. Gandolfi, A. Yu. Illarionov, K. E. Schmidt, et.al. Phys. Rev. C 79, 054005 (2009).
6. D. Lonardoni, I. Tews, S. Gandol_, and J. Carlson, arXiv:1912.09411 [nucl-th] (2019).

Masses of nuclei constitute an important part of the nuclear data required by many astrophysical models. We describe a method of obtaining Bayesian estimates of difference expressions of nuclear binding energies for medium and heavy nuclei, such as the residual neutron-proton interaction energy $\Delta_{np}$ and the well-known Garvey--Kelson expressions, using the Markov chain Monte-Carlo (MCMC) algorithm. Tikhonov regularization approach is used to impose the theoretically
expected requirement of smooth behaviour of the obtained estimates as a function of the nuclear mass number. With the help of these estimates an extrapolation of experimental nuclear masses from the AME database into the region of neutron- and proton-rich exotic nuclei is performed. The maximum range of extrapolation is determined by the estimated variance of the MCMC result and uncertainties of the experimental binding energies. The RMS error of masses of 65 new nuclei included in AME2020 in comparison with the prediction based on AME2016 amounts to 367 keV. The resulting mass values and nucleon drip lines are compared with other theoretical mass models at different values of the regularization parameter.

The properties of the collective low-lying states of Zr isotopes indicate that some of these states are mainly spherical and the other are mainly deformed ones. In our previous works [1,2], it was shown that the structure of low-lying collective states of $^{96}$Zr can be satisfactorily described within the framework of a geometric collective model based on the Bohr Hamiltonian with a potential that supports the existence of various forms of the nucleus. Based on these results, the question arises about the possibility of investigating the properties of low-lying collective states of $^{92−102}$Zr on the basis of a five-dimensional geometric quadrupole collective model.
The quadrupole-collective Bohr Hamiltonian depending on both $\beta$ and $\gamma$ shape variables with a potential having spherical and deformed minima, is applied. The relative depth of two minima, height and width of the barrier, rigidity of the potential near both minima are determined so as to achieve the best possible description of the observed properties of the low-lying collective quadrupole states of $^{92−102}$Zr.
Satisfactory agreement with the experimental data on the excitation energies and the E2 reduced transition probabilities is obtained. The evolution of the collective potential with increase of $A$ is described and the distributions of the wave functions of the collective states in $\beta-\gamma$ plane are found.
It is shown that the low-energy structure of $^{92−102}$Zr can be described in a satisfactory way within the Geometrical Collective Model with the Bohr Hamiltonian. The $\beta$-dependence of the potential energy is fixed to describe the experimental data in a best possible way. The resulting potential evolves with 𝐴 increase from having only one spherical minimum in $^{92}$Zr, through the potentials having both spherical and deformed minima, to the potential with one deformed minimum in $^{102}$Zr. A $\beta$-dependence of the wave functions is presented in a set of figures illustrating their distribution over $\beta$ [3].

1. E. V. Mardyban, E. A. Kolganova, T. M. Shneidman, R. V. Jolos, and N. Pietralla, Phys. Rev. C 102, 034308 (2020).
2. D. A. Sazonov, E. A. Kolganova, T. M. Shneidman, R. V. Jolos, N. Pietralla, and W. Witt, Phys. Rev. C 99, 031304(R) (2019).
3. E. V. Mardyban, E. A. Kolganova, T. M. Shneidman, R. V. Jolos, Phys. Rev. C 105, 024321 (2020).

A comprehensive analysis of the isoscalar giant monopole resonance (ISGMR) has long been a subject of extensive theoretical and experimental research [1,2]. The ISGMR properties are presently an important problem not only from the nuclear structure point of view [2,3] but also because of the special role they play in many astrophysical processes such as prompt supernova explosions [4] and the interiors of neutron stars [5].

The random phase approximation (RPA) with the Skyrme-type energy density functional (EDF) is the most widely used theoretical model for describing the ISGMR [2,3]. The study of the monopole strength distribution in the region of giant resonance involves taking into account a coupling between the simple particle-hole excitations and more complicated (two- and three-phonons) configurations [3,6]. The main difficulty is that the complexity of calculations beyond standard RPA increases rapidly with the size of the configuration space, and one has to work within limited spaces. Using a finite rank separable approximation for the residual particle-hole interaction derived from the Skyrme EDF one can overcome this numerical problem [7,8].

In the present report, we discuss the effects of the coupling between one-, two-, and three-phonon terms in the wave functions on the monopole strength distribution in the double-magic nuclei 40,48Ca. Using the same set of parameters, we describe available experimental data [9,10]. The effects of the phonon-phonon coupling (PPC) lead to a redistribution of the main monopole strength to lower energy states and into higher energy tail [11]. The PPC predictions of the fine structure of the ISGMR in the Ca isotopes are in good agreement with the fine structure which is extracted from experimental data analysis [12].

This work was supported by the Russian Science Foundation (Grant No. RSF-21-12-00061).

1. J.P. Blaizot, Phys. Rev. 64, 171 (1980).
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5. N.K. Glendenning, Phys. Rev. Lett. 57, 1120 (1986).
6. V.G. Soloviev, Theory of Atomic Nuclei: Quasiparticles and Phonons. Bristol/Philadelphia 1992.
7. N.V. Giai, Ch. Stoyanov, and V.V. Voronov, Phys. Rev. C. 57, 1204 (1998).
8. A.P. Severyukhin, V.V. Voronov, and N.V. Giai, Eur. Phys. Jour. A. 22, 397
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10. S.D. Olorunfunmi et al., Phys. Rev. C. 105, 054319 (2022).
11. N.N. Arsenyev, and A.P. Severyukhin, Phys. At. Nucl. 85, (2022) in press.
12. S.D. Olorunfunmi et al., in preparation.

The design of nuclear installations based on accelerators (or Accelerator Driven Systems - ADS) requires sufficiently accurate data on the total and differential cross sections for nuclear fission by neutrons with energies up to several hundred MeV. The situation with the reliability and completeness of such data and other important characteristics associated with them, which cannot always be directly measured in the interaction of neutrons with nuclei, can be significantly improved by modeling such interactions. However, the current state of the theory of nuclear fission, based on the model of transition states at fission barriers, is not entirely satisfactory. A reasonable description of the dependence of the fission cross sections on the neutron energy is achieved only by using a very significant number of adjustable parameters. This is connected, in particular, with insufficient information about the spectra of transition states. Such information can be obtained if not only total but also differential fission cross sections are included in the simulation process. Indeed, according to the same model of transition states, the angular distribution of fragments is determined by how the fission probability depends on the projection K of the spin of the fissioning nucleus onto the nucleus deformation axis at the barrier. However, this dependence is determined by what values of K characterize the rotational bands of transition states at the barriers. This work briefly describes the current state of experimental studies of the total and differential cross sections for nuclear fission by neutrons with energies up to 200 MeV, as well as the progress made in calculating these characteristics.

**Heavy-ion-induced projectile fragmentation reactions at Fermi energies are of interest to investigate the properties of nuclei far from the valley of stability, to know more about nuclear potential and equation of state of nuclear matter. These reactions are also useful to obtain exotic nuclei to be used as secondary beams. The reaction mechanism of these reaction is complicated, this energy region is in between the deep-inelastic collisions and direct reactions. This can be seen from the shape of velocity distributions of fragments. These distributions are peaked at project velocity, which is usual at relativistic energies. But they have long tail to the lower velocities due to deep-inelastic mode of the reaction. Here we treat such reactions in a microscopic approach [1], which consists of several steps: initialization of ground states of the colliding nuclei, dynamical evolution until the freeze-out point, calculation of the excitation energy of the primary fragments, and their de-excitation by emission of particles and radiation. For the dynamical evolution we use a Boltzmann--Vlasov type transport method, and for the de-excitation a statistical multi-fragmentation description. We apply this approach to collisions of 40Ar projectile nuclei on 9Be target, and calculate isotope distributions and velocity spectra of the produced isotopes. We compare the results of our calculations to experimental data obtained at COMBAS set-up in FLNR, JINR [2].

REFERENCES

1. T. I. Mikhailova, B. Erdemchimeg, A. G. Artukh, et al., Phys. of Atom. Nucl., 2016, V79 , P. 604.
2. Artukh, A. G., Klygin S.A., Kononenko G. A. et al. // PEPAN, 2016,V 47, P 49.
   **

Solar cosmic rays are generated during the primordial energy release in solar flares. This explosive process takes place in the solar corona above the active region at altitudes of 15 000 to 70 000 km. It represents the fast release of the magnetic field energy of the current sheet, which is formed near a singular magnetic field line under the influence of disturbances propagating from the solar surface. Solar cosmic rays appear as a result of acceleration of charged particles, mainly protons, by an inductive electric field in the current sheet, equal to the field $\bf{E} = \bf{V} \times \bf{B} / c$ near the current sheet. To study the mechanism of solar flares, the process of formation of a current sheet and the accumulation of energy in its magnetic field for each specific flare, and to obtain the possibility of improving the prognosis of solar flares based on an understanding of their physical mechanism, it is necessary to carry out magnetohydrodynamic (MHD) simulation of a flare situation in the solar corona above a real active region. The electric and magnetic fields obtained by MHD simulation above a real active region at the site of the primordial flare energy release and near it are necessary for studying the generation of solar cosmic rays. The acceleration of charged particles and the possibility of their exit from the acceleration region must be studied by calculating the trajectories of charged particles in electric and magnetic fields obtained by MHD simulation. The first results of studying the acceleration of charged particles were obtained by calculating trajectories in electric and magnetic fields, found by MHD simulation above the active region under simplified conditions.

When setting the conditions for MHD simulation, no assumptions were made about the physical mechanism of the solar flare; the boundary conditions were taken from observations. Experience has shown that the physical mechanism of a solar flare can be studied by MHD simulation only if the calculation starts a few days before the appearance of flares, when magnetic energy for the flare has not yet accumulated in the corona. For MHD simulation in the real scale of time, a significant computational speed is required, which is achieved only through the use of parallel computing on supercomputers. Parallelization of calculations was carried out by computational threads on graphic cards (GPU).

The MHD simulation above a real active region is continued, the results of which were presented at previous ICPPA conferences. The conditions for setting the problem of MHD simulation are refined, the developed method for the numerical solution of the equations of magnetohydrodynamics is improved. Simulation above the active region of AO 10365 in real time showed the appearance of a numerical instability near the boundary of the computational region, which has time to develop over a fairly long (about 3 days) time interval, despite use of the finite-difference scheme which is developed for our purposes. The scheme is absolutely implicit and conservative with respect to the magnetic flux. Methods for stabilizing emerging numerical instabilities were developed, which made it possible to solve the problem for relatively large usual and magnetic viscosities (usual and magnetic Reynolds numbers are $Re=10^4$; $Re_m=3 \times 10^5$). These methods made it possible to partially solve the problem of stabilization of instabilities for relatively low usual and magnetic viscosities ($Re = 10^7$; $Re_m = 10^9$), at which the perturbation propagating from the solar surface is weakly suppressed by the viscosity, which allows the formation of sufficiently powerful current sheets with high magnetic energy, accumulated for flare. The results obtained made it possible to understand how to further develop methods for stabilizing numerical instabilities.

MHD simulations showed the appearance of current sheets in the vicinity of X-type singular magnetic field lines. The configuration of the magnetic field above the active region is so complicated that the positions of singular lines and current sheets can only be found using a specially designed graphic search system. A divergent magnetic field can be superimposed on the X-type magnetic field configuration near the singular line. The divergent magnetic field may dominate, so that the resulting configuration will not resemble an X-type field. However, due to the presence of an X-type configuration in the superimposed fields, MHD simulations show the formation of a current sheet. At the sites of the flares on May 26 and 27, 2003 above AR 10365, the X-type configuration is strongly distorted by the diverging magnetic field. Perhaps for this reason, the solar flares on May 26 and 27, 2003 were not very strong. The coincidence of the position of the flare thermal X-ray source with the places on singular lines where the current sheet was formed confirms the solar flare mechanism based on the accumulation of energy in the magnetic field of the current sheet.

Diffusion of relativistic runaway electron avalanches

One of the unsolved problems in atmospheric physics is the construction of a model of Terrestrial Gamma-ray Flashes (TGFs). This phenomenon was first discovered in 1994 by Compton Gamma Ray Observatory [1] and was observed by other space gamma-ray observatories such as Fermi [2], which were created for observing gamma radiation from astrophysical sources. It has been established that avalanches of relativistic runaway electrons avalanches (RREA) accelerated by an electric field in thunderclouds are the sources of these bursts [3]. However, research shows that the existence of RREA is not sufficient to generate a TGF [4]. In an attempt to settle this issue a model of relativistic feedback mechanism was suggested by Joseph Dwyer. The Dwyer model does not take into account diffusion of RREAs and the finite transverse size of the accelerating region. RREAs of new generations resulting from feedback may be created outside the acceleration region, which may lead to a decrease in the number of new avalanches and an increase in the requirements for self-sustaining RREA production by the feedback.

In this work the transverse propagation of avalanches was described using a modified two-dimensional diffusion equation. A correction to the criterion for self-sustaining production of RREAs was obtained:

$\Gamma_d = \Gamma \cdot \exp(-\left(\frac{2.403}{R}\right)^2 D \tau)$

Here $\Gamma$ is a feedback coefficient without correction, R is the transverse size of the accelerating area and $D \tau$ is the diffusion coefficient multiplied by the average time of creation of new generation. Monte Carlo simulation using GEANT4 was also performed to calculate the correction to feedback coefficient. For example, for an air density corresponding to an altitude of 10 km above sea level for an acceleration zone with a size of 400 m in the longitudinal direction and 500 m in the transverse direction $\Gamma_d \approx 0.99 \cdot \Gamma$. It can be seen that taking into account the transverse size does not make a significant contribution to the feedback coefficient and therefore almost does not distort the criterion for self-sustaining RREA production.

References

1. Fishman G. J. et al. Discovery of intense gamma-ray flashes of atmospheric origin //Science. – 1994. – Т. 264. – N. 5163. – С. 1313-1316.
2. Mailyan B. G. et al. The spectroscopy of individual terrestrial gamma‐ray flashes: Constraining the source properties //Journal of Geophysical Research: Space Physics. – 2016. – Т. 121. – N. 11. – С. 11,346-11,363.
3. Dwyer J.R. A fundamental limit on electric fields in air //Geophysical Research Letters. – 2003. – Т. 30. – N. 20.
4. Gurevich A. V., Zybin K. P. Runaway breakdown and electric discharges in thunderstorms //Physics-Uspekhi. – 2001. – Т. 44. – N. 11. – С. 1119.

Previously, all studies in this area of atmospheric physics, namely, avalanches of relativistic runaway electrons (RREA), were carried out without taking into account the presence of hydrometeors in thunderclouds, which could seriously affect the results and their correspondence to actually observed natural phenomena. Such as TGF(Terrestrial Gamma-ray Flash) and TGE(Thunderstorm Ground Enhancements), the cause of which is still not clear; which are observed in astroparticle experiments, for example, on the Fermi Gamma-ray Space Telescope. This talk takes into account hydrometeors in clouds. In this work, the distribution of RREA was simulated in GEANT4 was simulated taking into account various concentrations of ice particles. Modeling showed that accounting for the presence of hydrometeors cannot be simplified and reduced to a change in the main substance.
Two methods are considered - modeling of volumetric hydrometeors as separate modeling objects and as a simple change in the components of a whole substance (adding water to air with a corresponding density). These methods show completely different results.
Modeling by volumes of hydrometeors shows a decrease in the length of the avalanche by 20 %, on the other hand, when modeling with a modified material, the length changed only by 1 %. This suddenly proves that hydrometeors should be taken into account in research, as they can significantly change the growth length of an avalanche in real thunderstorm condition.

The physical motivations and performance of the TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) project are presented. The TAIGA observatory addresses ground-based gamma-ray astronomy at energies from a few TeV to several PeV, as well as cosmic ray physics from 100 TeV to several EeV and astroparticle physics. The pilot TAIGA-1 complex locates in the Tunka valley, ~50 km West from the southern tip of the lake Baikal. It includes integrating air Cherenkov TAIGA-HiSCORE array with 120 wide-angle optical stations distributed over on area 1.1 square kilometer about and three the 4-m class Imaging Atmospheric Cherenkov Telescopes of the TAIGA-IACT array. The latter array has a shape of triangle with side lengths of about 300m, 400m and 500m. The integral sensitivity of the 1 km$^2$ TAIGA-1 detector is about $2,5 × 10^{-13}$ TeV cm$^{-2}$ sec$^{-1}$ for detection of $E\ge100$ TeV gamma-rays in 300 hours of source observations. The combination of the wide angle Cherenkov array and IACTs could offer a cost effective-way to build a really large (up to 10 km$^2$) array for very high energy gamma-ray astronomy. The reconstruction of a given EAS energy, incoming direction and the core position, based on the TAIGA-HiSCORE data, allows one to increase the distance between the relatively expensive IACTs up to 600-800 m. These, together with the surface and underground electron/Muon detectors will be used for selection of gamma-ray induced EAS. Present status of the project, together with the current array description and the first experimental results and plans for the future will be reported.

The Telescope Array (TA) is the largest cosmic ray observatory in the Northern Hemisphere. It is designed to measure the properties of cosmic rays over a wide range of energies. TA with it's low energy extension (TALE) observe cosmic ray induced extensive air showers between 2x10^15 and 2x10^20eV in hybrid mode using multiple instruments, including an array of scintillator detectors at the Earth's surface and telescopes to measure the fluorescence and Cerenkov light. The statistics at the highest energies are being enhanced with the ongoing construction of the TAx4 experiment which will quadruple the surface area of the detector. We review the present status of the experiments and most recent physics results on the cosmic ray anisotropy, mass composition and energy spectrum. Notable highlights include a new feature in the energy spectrum at about 10^19.2 eV, a new clustering of events in their arrival directions above this energy and an indirect estimation of heavy mass composition at energies higher than 10^20 eV.

The complementary approach to the investigations of extensive air showers (EAS) is very promising for conducting their multicomponent studies. In this approach, information about one or more EAS components, which is insignificant from the point of view of independent analysis, can be added to data on other components providing more accurate determination of the parameters of the extensive air shower and the primary particle.
Such studies and an approach have been implemented at the Experimental complex NEVOD (MEPhI, Moscow), which includes installations capable of detecting electron-photon, hadronic and muon components of extensive air showers by various methods.
All installations of the Experimental complex NEVOD are combined by a global time synchronization system, which allows linking of events detected by each installation to the global time with an accuracy of 10 ns. For the joint analysis of information from all installations of the complex, a unified database of experimental data is being developed.
In this report, we present examples of events detected by the installations and detectors of the complex, discuss EAS characteristics and the results of joint analysis of experimental and simulated data on various air-shower components.

In a number of experiments on the study of ultrahigh-energy cosmic rays, an excess of muons in extensive air showers in comparison with calculations performed within modern (post-LHC) models of hadronic interactions is observed. An analysis of the NEVOD-DECOR data over a long period of time indicates an increase in the excess of muon bundles with increasing energy of primary cosmic ray particles, so that at ~ 10^18 eV the intensity is consistent with the expected one only under the assumption of an extremely heavy mass composition. The key to explaining the excess of muons may be the study of the energy characteristics of muon bundles, that are conducted in the NEVOD-DECOR experiment. Recently, estimates of the average muon energy in the bundles were obtained and its increase compared to the results of calculations at energies above 10^17 eV was found. Thus, the solution of the muon puzzle may require major changes to the existing models of hadron interactions.

Two installations currently operating as part of the TAIGA Astrophysical Complex [1]: TAIGA-HiSCORE [2] -120 wide-angle Cherenkov stations on an area of 1 $km^2$ and TAIGA-IACT[3] - 3 IACTs, are playing the most important role in research in the field of very high-energy gamma-ray astronomy. The large area and unique methodological capabilities of the complex allow us to hope for new and interesting results.

The report focuses on the analysis of date of the Crab Nebula observation in stand-alone and stereo modes of observation. The techniques for selecting gamma-like events and approaches for the energy reconstruction in these modes of observation are discussed.

Based on the date of the first IACT, for 150 hours of observation, the excess of gamma-rays at the significance level of 12σ (618 events) was obtained. From 36 hours of operation of two telescopes in stereo mode excess of gamma rays at the significance level 5σ was obtained.
The energy spectra of gamma-rays in the energy range 4-80 TeV reconstructed both by stand-alone and stereo modes are presented.

1. L. A. Kuzmichev et al. Cosmic ray study at the astrophysical complex TAIGA: Results and plans // Physics of Atomic Nuclei. — 2021. — Vol. 84, no. 6. — P. 966–974.
2. O. A. Gress et al. The wide-aperture gamma-ray telescope TAIGA-HiSCORE in the Tunka Valley: Design, composition and commissioning, Nucl. Instrum. Meth. A 845 (2017) 367.
3. N. B. Lubsandorzhiev Camera of the first TAIGA-IACT: construction and calibration, PoS ICRC2017. 757

In this work, anomalous events recorded by the TUS space detector are considered. In this research we try to give interpretation of this anomalous events, which, mostly, are caused by the thunderstorm activity. Different interpretations of this events like gamma-ray bursts, synchrotron radiation in the geomagnetic field of electrons/positrons in cosmic rays, an ascending extensive air shower, as well as their hardware nature was considered as their possible sources. An analysis of these events may for the first time confirm the connection between thunderstorm activity and extensive air shower.

Observations of monthly electron and positron fluxes made from 2006 by PAMELA experiment continue investigation of the relative modulation of positively and negatively charged particles.
The comparison of the electron fluxes with proton and positron fluxes measured at about 1 GV in 23th and 24th solar cycles is presented.

We present a short discussion of the Neutrino-4 experimental results and the results of other experiments searching for the sterile neutrino. We estimated the contribution of the sterile neutrino with parameters $\Delta m^2_{14} \approx 7.3 \text{eV}^2$ and $\sin^22\theta_{14} \approx 0.36$ obtained in the Neutrino-4 experiment to the energy density of the Universe. We address the contradiction between the measured sterile neutrino parameters and the constraints on the sterile neutrino from cosmology. With this article, we want to draw attention to the problem of the contradiction between experiment and theory, in order to inspire the search for theoretical models that include a sterile neutrino with mass in the region of several eV, and to the necessity to sufficiently increase the precision of the experiment.

Solid state spectrometer of reactor antineutrino DANSS is placed
below the core of the 3.1 GWt_th industrial nuclear reactor of
Kalininskaya NPP. In the closest position to the reactor
the detector counts more than 5000 inverse beta-decay (IBD) events
per day with background below 2 %. The distance to the reactor is
changed weekly between 10.9 and 12.9 m, which allows to make a
model-free search for a short range neutrino oscillations. Spectrum
evolution with the distance is measured directly by the same detector.

The talk is based on the statistics of 6 million events,
obtained during 6 years between April 2016 and March 2022.
We present limits in the short range oscillation
parameter space. We also compared the anti-neutrino
energy spectrum with theoretical predictions and
confirm a bump in their ratio similar to the bumps
observed in several other experiments.

DANSS is a one cubic meter highly segmented solid scintillator detector. It consists of 2500 scintillator strips, covered with gadolinium loaded reflective coating and read out with SiPMs and PMTs via wavelength shifting fibers. DANSS is placed under a 3.1 GW industrial reactor at the Kalinin NPP (Russia) on a movable platform. The distance from the reactor core center is varied from 10.9 m to 12.9 m on-line. The inverse beta decay (IBD) process is used to detect antineutrinos. DANSS detects about 5000 IBD events per day with the background from cosmic muons at the level of few percent.
In this talk we present results on the neutrino spectrum dependence on the fuel composition. We have also measured the reactor power using the IBD event rate during almost 6 years with the statistical accuracy 1.5% in 2 days and with the relative systematic uncertainty of about 0.5%. The limits in sterile neutrino parameter space based on information about absolute counting rates are also presented.

Industrial Detector of REactor Antineutrinos for Monitoring (iDREAM) is a prototype detector designed to demonstrate the feasibility of antineutrino detectors for remote reactor monitoring and safeguard purposes. The 1 ton Gd-doped liquid scintillator detector is mounted in the Kalinin nuclear power plant (Russia), 20 m from the 3 GW$_{th}$ VVER type commercial reactor. Antineutrinos are detected via inverse beta decay on protons. The detector took data both in reactor ON and OFF modes. In this talk the iDREAM measurements of the accidental and correlated backgrounds will be discussed. The iDREAM antineutrino data and the detector prospects will be reviewed in the framework of applied antineutrino physics.

New antineutrino spectra of fissile isotopes constituting the fuel of a nuclear reactor have been obtained. A combined technique was used: calculation of the antineutrino spectra and their fitting to those obtained in the experiment at the Rovno NPP in the 1980s. The cross sections of fissile isotopes calculated with these spectra perfectly describe the experimentally obtained cross section in the Double Chooz experiment $^{DC}\sigma_f = (5.71 \pm 0.06) \cdot 10^{-43}$ cm$^2$/fission. The cross section obtained from the calculated spectra for the same composition of nuclear reactor core $^{INR}\sigma_f = (5.82 \pm 0.12) \cdot 10^{-43}$ cm$^2$/fission. For the obtained spectra, there is no problem of spectrum bump in the region of 5 MeV in the observed energy of the positron spectrum.

In measurements with intense artificial sources of monochromatic neutrinos on gallium targets, a capture rate equal to 0.80 ± 0.05 of the expected was obtained. The measured lack of capture rate is known as the gallium anomaly (GA). Neutrino oscillation transitions with large values of the parameter Δm2 (~ 1 eV2) are considered a possible cause of GA. In the proposed BEST-2 experiment, the GA will not only be tested with high accuracy, but also the parameters of the oscillations will be measured if they are in the sensitivity range of the experiment. In the BEST-2 experiment, a gallium target consisting of 50 tons of metallic gallium and divided into 3 independent zones will be irradiated with neutrinos from a 65Zn source.

The COHERENT collaboration aims to test the Standard model with the help of coherent elastic neutrino-nucleus scattering (CEvNS). The experimental effort involving multiple detectors takes place at the Spallation Neutron Source in Oak Ridge National Laboratory. In this talk we decribe the results, status, and prospects of the COHERENT program. In particular, recently evaluated limits on the non-standard neutrino-quark couplings and parameters of accelarator produced dark matter are presented.

The $\nu$GeN experiment is aimed to study neutrino scattering at the close vicinity of the reactor core of Kalinin Nuclear Power Plant (KNPP) at Udomlya, Russia. Its main interests are connected with the detection of coherent elastic neutrino-nucleus scattering (CE$\nu$NS), the search for the magnetic moment of neutrino and other rare processes. The experimental setup is constructed under reactor unit #3 of KNPP at a distance of about 10 m from the center of the 3.1 GW$_{th}$ core. In this way, we obtain an enormous antineutrino flux of more than 5x10$^{13}$ $\nu$/cm$^2$/s. Materials of the reactor surrounding provide about 50 m w.e. overburden, that serves as a good shielding against cosmic radiation. In combination with a low ambient background, it gives us a unique opportunity to investigate antineutrino properties at the best experimental location in the world. A special lifting mechanism allows moving the spectrometer towards the reactor core changing the neutrino flux and thus suppressing main systematic errors caused by possible long-term instability and insufficient knowledge of neutrino flux. To detect signals from the neutrino scattering we use high-purity low-threshold germanium detector surrounded by passive and active shielding. A specially developed acquisition system allows suppressing events that correspond to noise. A detailed description of the experimental setup will be shown. The current status of data taking and comparison of the spectra with reactor on and off regimes will be presented.

The RED-100 two-phase emission detector with 200 kg of liquid xenon as a working medium was exhibited at a distance of 19 m from the core of the VVER-1000/320 nuclear power reactor at the 4th power unit of the Kalinin NPP in 2021-2022. Due to its high sensitivity to weak ionization signals (down to single electrons), the RED-100 detector was used to observe elastic coherent scattering of electron antineutrinos off xenon nuclei. A set of experimental data was obtained in the regimes with the reactor on and off. The results obtained are discussed.

The absolute polarimeter for measurements of proton and antiproton beam polarizations at the SPASCHARM experiment at U-70 of IHEP, Protvino, is discussed. Polarized target will be used to measure analyzing power AN of the elastic reactions. Measured value of AN is required to define beam polarization. Two different detectors of the experimental setup were analyzed. The first one is supposed to use scintillation counters, the second detector is based on proportional chambers. Efficiency of registration of elastic pp scattering is compared for two configurations of the experimental setup.

The possibility to use the pp-, pd- and dd- elastic scattering for the polarimetry at NICA using the existing experimental data is discussed. The first results of the simulation of these processes at the total energy up to 27 GeV for the segmented scintillation counter are presented.

Data taking has been started at the first stage of the polarization experiment SPASCHAR$M at U70 accelerator. The report describes the detectors of the current experimental setup as well as the results of measurements of their characteristics during the beam data taking in the runs of 2018-2022

Antineutron studies are an unexplored domain of high energy physics. Several directions of research can be outlined, such as: measuring of hadrons decaying into antineutrons, measuring the interaction of antineutrons with hadrons, and searching for bound states of antineutrons. We present a method for measuring antineutrons by the electromagnetic calorimeter PHOS of the ALICE experiment. The antineutron can be identified by the cluster shape and the energy deposition in the calorimeter, and its momentum can be reconstructed using time-of-flight information. The proposed method was verified via searching for decays $\bar{\Sigma}^{+}\rightarrow\bar{n}\pi^{+}$and $\bar{\Sigma}^{-}\rightarrow\bar{n}\pi^{-}$with an antineutron reconstructed in PHOS.

T2K (Tokai to Kamioka) is the first long-base neutrino experiment with the concept of an off-axis neutrino beam generated by a 30 GeV proton synchrotron (PS) based on the Japan Proton Accelerator Research Complex (J-PARC).
This project is aimed at finding of a new source of violation of charge-conjugation parity-reversal CP-symmetry in the neutrino sector - a necessary element for explaining physical phenomena beyond the Standard Model, namely the baryon asymmetry of the Universe (the matter-antimatter disparity) and leptogenesis.
Currently, the T2K experiment excludes the CP-conservation ($\delta_{CP} = 0,\pi$) at the level of 90% CL [1]. In order to increase its sensitivity to CP-violation, it is necessary to reduce systematic uncertainties in predicting the number of events at the far water Cherenkov detector Super-Kamiokande up to 3-4% from the current level of 6-7%. Thus, an intensive upgrade program of the ND280 off-axis detector was launched [2]. As a part of this upgrade, a new fully segmented 3D neutrino scintillation detector SuperFGD was proposed and designed. It will allow precision measurements of neutrino cross-sections and significantly increase the sensitivity to CP-violation in long-base experiments.
SuperFGD with a total weight of about two tons, consisting of two million optically isolated cubes, each of them with a volume of 1 cm$^3$ and with three holes for inserting wavelength shifting fibers (a total of 60,000 channels for signal readout), was produced in Russia and will be a key element of the new upgraded near detector of the T2K experiment. All active 56 layers of the SuperFGD and the assembly platform have been shipped to Japan in June 2022. The assembly of the SuperFGD was started at J-PARC in October 2022.
Such important components of the SuperFGD detector as electronics, mechanics, photosensors, LED calibration system, DAQ are also being actively prepared and will be discussed. The current status and upcoming plans for the SFGD as a part of the ND280 upgrade will be presented at the conference.

References

[1] K. Abe, et al., Constraint on the matter-antimatter symmetry-violating phase in neutrino oscillations, Nature 580 (2020) 7803, 339-344. arXiv:1910.03887.

[2] K. Abe, et al., T2K ND280 Upgrade - Technical Design Report. arXiv:1901.03750 
[physics.ins-det].

The annihilation photons are the first system where the entanglement of quantum states was experimentally studied. These photons are produced in the positron-electron annihilation and have 511 keV energy that coincides with the electron mass. According to the theory, two photons have mutually perpendicular linear polarizations, and their quantum states are entangled. Inspite of extensive studies the entanglement was not experimentally proved due to the low efficiency of Compton polarimeters that are the only tool for the polarization measurements of photons with such a high energy. We constructed the setup that allows a direct comparison of polarization correlations for both, entangled and decoherent quantum states. The natural expectation is observation of principal differences in behavior of these two different quantum states. Nevertheless, the experimental results reveal the same behavior in the polarization correlations of both, entangled and decoherent states. We discuss the construction of setup, Monte Carlo simulation and the experimental measurements of entangled and decoherent annihilation photons. A physical interpretation of the data is presented.

DANSS detector at Kalininskaya nuclear power plant sets world records in antineutrino detection. Counting rates of up to 5000 events per day made it possible to collect more than 6.5 million antineutrinos in 6 years of stable operation. The data sample is extremely clean and features the signal to background ratio in excess of 50. Yet only moderate energy resolution of 34% at 1 MeV limits the sensitivity of the experiment for the sterile neutrino searches.
The upgrade of the detector is aimed at more than twice better energy resolution of 12% at 1 MeV. Besides that the sensitive volume will be increased by 70% inside the same shielded space on the lifting platform. The talk will address the details and the status of the upgrade together with the first results of testing. The expected influence of the improvements on the sensitivity for the sterile neutrino will also be discussed.

Aging of the plastic scintillators plays a significant role in the degradation
of detectors performance. Several effects are considered responsible for
this process like mechanical stresses, water penetration and oxidation.
The DANSS detector core consists of 2500 polystyrene based scintillation strips.
The detector is located just below an industrial nuclear reactor
of Kalininskaya NPP. The room housing the detector is air conditioned and
has very low humidity. The temperature of about 20C was sustained at
the detector core. The performance of the scintillator is permanently
monitored with cosmic muons passing through the detector. 6 years of
observation are reported since April 2016 till March 2022. The light yield
degradation about 1% per year is observed.

Semileptonic flavor changing neutral current transitions of $B$-mesons with a pair of neutrinos in the final state are very accurately determined in the standard model (SM) and, thus, provide a sensitive probe for physics beyond the SM. Until recently, the poor tagging efficiency for the $B\to K^{(*)}\nu\bar{\nu}$ modes made them less advantageous as a probe of new physics (NP) compared to the charged lepton counterparts. The most recent Belle II result on $B^+\to K^+\nu\bar{\nu}$ indicates a possible enhancement in the branching fraction of $B^+\to K^+\nu\bar{\nu}$. Therefore we explore the possibilities of an enhancement in a set of observables for $B\to K^{(*)}\nu\bar{\nu}$. We considered the weak effective theory extended by vector effective operators both with light left- and right-handed neutrinos. The latter can appear in various SM extensions, e.g., in models with additional $Z'$ boson.

The production cross sections of charmonia, charmonium-bottomonium and bottomonia pairs in a single boson electron-positron annihilation have been studied in a wide range of energies, which will be achieved at future e+e− colliders such as ILC and FCC. Color singlet contributions to the vector and pseudoscalar state production are taken into account. NLO QCD and LO EW contributions, as well as their interferences are considered. Both intermediate bosons, γ and Z, are included. All calculations are performed in terms of perturbative technique and NRQCD-factorization.

We study the prompt single and double J/ψ hadroproduction in the Improved Color
Evaporation Model using the Parton Reggeization Approach. We make calculations in a single manner to described the experimental data for prompt J/ψ transverse momentum spectra from the energy of $\sqrt{s}$=19 GeV up to modern energy of the LHC, $\sqrt{s}$=13 TeV. The numerical calculations are made using parton-level MC generator for kT−depended initial-state partons, KaTie. We use the modified KMR-type unintegrated parton distribution functions of Reggeized gluons and quarks with exact normalization based on Kimber-Martin-Ryskin-Watt model. We suggest improvement of the ICEM for the pair-production of J/ψ. In case of double J/ψ production we investigate the relative contributions of the single-parton scattering and double-parton scattering mechanisms.

A number of resonances compatible with a hypothesis of hidden-charm pentaquark was observed by the LHCb Collaboration. We interpret these narrow resonances as compact hidden-charm diquark-diquark-antiquark pentaquarks. Within this assumption, an interplay between the charmonium and open-charm modes is considered. Ratios of such modes is estimates for non-strange and strange pentaquarks are obtained and discussed.

This work is supported by the Russian Science Foundation (Project № 22-22-00877, https://rscf.ru/project/22-22-00877/).

The total cross section of the process $e^+e^- \to \Lambda\bar{\Lambda}$ is calculated within the energy range close to the mass of $\psi(3770)$ charmonium state. Two different contributions were considered: the $D$-meson loop and the three gluon charmonium annihilation one. Both of them contribute noticeably and
in sum fairly reproduce the data. Large relative phase for these contributions are generated with respect to the pure electromagnetic mechanism. As a by product the fit for the electromagnetic form factor of $\Lambda$-hyperon is obtained for large
momentum transferred region.

Masses of the ground and excited states of the fully-heavy tetraquarks, composed of charm $c$ and bottom $b$ quarks and antiquarks, are calculated in the diquark-antidiquark picture in the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The quasipotentials of the quark-quark and diquark-antidiquark interactions are constructed similarly to the previous consideration of mesons and baryons. Relativistic effects are consistently taken into account. A tetraquark is considered as a bound state of a diquark and an antidiquark. It is assumed that the diquark and antidiquark interact in the tetraquark as a whole, and the internal structure of the diquarks is taken into account. Most of the investigated states of tetraquarks are found above the thresholds of decays to two heavy quarkonia. This is a result of the consideration of the diquark not to be a pointlike object. Therefore, such tetraquarks can be observed only as broad resonances decaying dominantly to quarkonia. The narrow state X(6900) recently discovered in the di-$J/\psi$ production spectrum by the LHCb, CMS and ATLAS Collaborations corresponds to an excited state of the fully-charmed tetraquark. Other recently discovered exotic charmed resonances X(6200), X(6400), X(6600), X(7200), X(7300) can also be interpreted as the different excitations of the fully-charmed tetraquark.

We study the processes of the paired heavy meson and baryon production in electron-positron annihilation, gamma-gamma interaction and decays of the Higgs boson. Using the perturbative Standard Model and relativistic quark model we construct relativistic amplitudes and cross sections. Relativistic corrections connected with the relative momenta of heavy quarks are calculated in the production amplitudes and wave functions of the bound states. Numerical results for different production cross sections are presented.

The processes with single top quark production provide a prototype search for the types of final state that are expected in many new physics scenarios. Some distinctive features are considered for particle production in the top sector in ultra-high energy domain which can be covered partly in the collisions of cosmic ray particles with atmosphere. The single top quark production through electroweak interaction is studied within the Standard model and the Effective field theory approach used for calculations of total partonic cross sections. These quantitative results can be important for both the future collider experiments at center-of-mass energy frontier and the improvement of the phenome-nological models for development of the cosmic ray cascades in ultra-high energy domain. Thus the study allows the better understanding of heavy particle production and emphasizes the exciting interrelation between the high-energy physics on accelerators and ultra-high energy cosmic ray measurements.

This report discusses one of the stages of work on the creation of artificial pinning centers in superconducting tapes, for the possible creation of a series of superconducting magnets based on them, operating at temperatures up to 65 K.
The report describes the experimental setup and the results of irradiation of the HTS samples in the neutron-proton field of the lead converter, analyzes the gamma spectrum measured with HPGe detectors, and determines the composition of isotopes of the samples after irradiation. The yields of isotopes were determined, allowing us to quantify the percentage of the neutron component in the flux passing through the sample in order to optimize the conditions for obtaining the matrix of defects necessary for the emergence of stable vortex pinning in the electromagnetic field of the superconductor. ( I = 10 13 p+/sm2/s ) * 9000 s

The behavior of a beam with elliptical cross-section and arbitrary partial emittances in a solenoid is studied analytically. Such analysis is needed for various tasks of accelerator physics, for example, the formation of the beam extracted from the ion source and for the Low Energy Beam Transport (LEBT) design. The peculiarities of the coupling of the beam oscillations in longitudinal magnetic field are investigated depending on the input beam parameters and the characteristics of the magnetic field, the modified KV-model being used. The results of the calculations are presented which describe the evolution of the beam parameters.

The availability of muons in a wide energy range makes it possible to offer them experiments on topical problems of nuclear physics. Answering questions of a fundamental nature, they can be used in research on geology and radiation biology related to the impact of muons of cosmic origin. It is possible to use relativistic muons in the muon torch and in the secondary particle channel of the U-70 accelerator.
Of primary interest is the possibility of fully detecting short-range α-particles produced in nuclear fragmentation events under the action of muons. The reaction µ + 12С → µ' + 3α is the starting point in the study of nuclear fragmentation under the action of muons. The presence of the 12C isotope in nuclear emission and organic scintillators makes it possible to use these materials as active targets.
Traditionally, radioactive decay of uranium, thorium and their daughter radionuclides is indicated as a source of helium, and analysis for the presence of helium serves to search for their deposits. At the same time, the reaction µ + 12С → µ' + 3α can serve as a mechanism for generating helium in natural gas fields.
Thus, it is necessary to measure the cross section for the reaction µ + 12С → µ' + 3α in the widest possible energy range on an active carbon-containing target, which combines detection of beam particles and triples of α-particles. In this regard, the following is proposed. A muon beam with an energy of 7 GeV is used, which can pass after one or two beam absorbers in the HYPERON channel. Muons are directed to a thin scintillator, which registers ionization losses, starting from the minimally ionizing particles of the beam and up to 3α stars. The background and development of this experiment are presented.

I.N. Borzov 1,2, S.V. Tolokonnikov1,3, S.S. Pankratov 1, A.V. Khudov4

1 National Research Centre “Kurchatov Institute”, Moscow, Russia.

2Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, Dubna, Russia.

3 Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia.

4 National Research Nuclear University MEPHI, Moscow, Russia.

E-mail: Borzov_IN@nrcki.ru, cc: ibor48@mail.ru

In the recent experiments at RILIS-CERN, the high precision measurements of nuclear charge radii and magnetic moments have been performed for heavy isotopes in the region of N=126. We will present our results of simultaneous analysis of the ground state characteristics in terms of the Fayans energy density functional DF3-a [1-3] newly tuned by variation of the previously unused volume (isovector) parameter h-2 [4].

Additional constraint is implemented from the upper bound of the giant dipole resonance energy in 208Pb. Also an extended set of restrictions on the symmetry energy and its slope at saturation density L(ρ0) for symmetric nuclear matter is applied. They were obtained from the data on nuclear masses, results of ab initio calculations with N3LO, the neutron skin (ΔRnp) values derived from PREXP-II, CREX experiments, augmented by the observational data on the radii of neutron stars and on gravitational waves registration (see [5]).

The systematic calculations of the charge radii and magnetic moments are performed for Pt to Bi isotopes and compared with the latest data [1-3] in the vicinity of neutron shell N=126.

Supported by the grant of Russian Scientific Foundation (RSF 21-12-00061).

1. A. Barzakh et.al., Phys.Rev. Lett.127, 192501 (2021).
2. T. Day Godrache et.al., Phys.Rev. C106, 034326 (2022).
3. Y. Нirayama et.al Phys.Rev. C106, 034326 (2022).
4. I.N. Borzov, S.V. Tolokonnikov, in report on the IPCAA-2022.
5. J. Lattimer in "The Modern Physics of Compact Stars and Relativistic
   Gravity”, Yrevan, Armenia, 2021.

Polarizability is a fundamental particle property. Measurement of pion
polarizability values allows checking strict ChPT prediction. Charged and
neutral pi-mesons polarizability will be extracted from the CPP and NPP
experimental data using Primakoff pair production cross-section on nuclear target. The CPP/NPP experiment run at TJNAF Hall-D was conducted in the summer of 2022 and utilized a polarized photon beam with an energy range of 4.5-6.0 GeV
and the lead-208 target on the upgraded GlueX experimental setup.

In this talk, we will discuss existing experiments that measured charged
pion polarizability, review CPP/NPP experimental data, future plans on
cross-section and polarizability of the charged and neutral pions (for the
first time) extraction.

Inclusion in Analysis of Borexino data K-40 antineutrino spectrum makes the fit better than without. Borexino data can install an upper limit on potassium abundance < 3% of Earth's mass. The probability to observe high K-40 counting rate in case of its absence is about 0.0001. It signals on large potassium abundance in the Earth.

Neutrino continue to be a source of scientific discoveries in nuclear physics, elementary particle physics, and cosmology. Two main conclusions of numerous experiments performed over past decades based on a variety of methods and with different sources of neutrinos are: i) neutrinos have nonzero mass, and ii) there is significant mixing between individual neutrino mass states. Despite these major breakthroughs, further experimental studies based on new experimental methods and using unexplored processes are urgently needed to go beyond the Standard Model, which, as we know from cosmology and particle physics, must be extended.

The history of neutrino physics is continuously linked with the reactors. It all started with the reactor based experiment [1], which first confirmed the existence of neutrinos. It is well known, that in a modern type WWER1000 reactors, an average of 200 MeV of energy is released per fission. At the same time, each fission is accomplished with emission on average of ~ 6 electron antineutrinos. Thus, a modern reactor, for example one at Kalinin NPP, emits ~ $6 \times 1020$ electron antineutrinos per second, having a continuous energy spectrum with maximum energies up to ~ 10 MeV. Therefore, even at a distance of tens of meters from the reactor, it remains the most powerful available source of antineutrinos, two orders of magnitude larger than the neutrino flux from the Sun. Given that neutrinos are only weakly coupled with other particles, a huge reactor antineutrino flux is often the only way to study the properties of neutrinos.

Russian science has a fruitful history of conducting experiments with reactor neutrinos at Rovno (Rivne NPP), Krasnoyarsk and Udomlya (Kalinin NPP) (works leading by L.A. Mikaelyan, A.A. Borovoy, V.P. Martemyanov and others). The talk will provide a general overview of Russian and some international neutrino experiments at reactors. The focus will be on experiments with the latest types of semiconductor, cryogenic and scintillation detectors. It will be demonstrated that by developing of fundamental tasks of neutrino detection, the possibility of applied use of neutrinos for remote monitoring of reactors is provided.

Keywords: neutrino, fundamental problems of modern physics, detectors.

Bibliography

1. Reines F., Cowan C.L. // Phys. Rev. 1953. V.90. P.49

The results of the study of the specific light output from the energy of X-rays and gamma quanta in the range from 1.5 to 662 keV for scintillation crystals NaI (Tl), CsI (Na), CsI (Tl), Bi4Ge3O12, CdWO4, ZnWO4, Y3Al5O12: Ce, CaF2 (Eu), LSO, YAlO3: Ce. The obtained dependences have a nonlinear form with pronounced minima in the region of the K and L edges of the absorption of the elements that make up the scintillators.
When X-ray and gamma quanta are recorded in the energy range from 1 to hundreds of keV, a strong change in the specific ionization losses of the produced photoelectrons dE / dx occurs in the scintillation crystal, there are K and L jumps in the crystal absorption cross section. All this has a significant effect on the light output of scintillators. The possibility of reducing the nonlinearity of the response of scintillators during the detection of gamma radiation is shown.

A method for finding the position of the sectors of the time projection chamber based on experimental data is proposed. Based on the results of modeling the response of the sensitive elements of the camera, three types of tracks were reconstructed: cosmic muons, beams of the laser detector system and muons from the interaction of nuclei. Using these artificial experiment data and the proposed method of finding the position of sectors, the accuracy of sector alignment was investigated. For cosmic and laser rays, the accuracy is approximately the same. It is ~700 microns for the shift of the origin of the sector and 7 angular minutes for Euler angles. The accuracy in the case of muons born in collisions of nuclei is several times worse.

Dark Matter particles that are constructed from proton-antiproton String Junctions (SJ,antiSJ) was already announced at ICPPA18. Essencial specifics in spectra of baryons in p-p interaction are leading to new implications for cosmic ray physics and astrophysics. VHE event in stratosphere has shown that the pattern of astroparticle collision differs from nucleus-nucleus interaction. It can be heavy baryonium DM particle that reached the Eath.
The form of proton spectrum in VHE p-p collisions has triplex-Pomeron peak at highest energy. The similar enhancements have been measured in cosmic spectra of gamma-photons and neutrinos. All these make us convinced that spectra of cosmic particles are formed in the first UHE proton collision near SMBH. Calculations have been resulted in the value of initial energy of protons of the order of $10^{12}$ GeV.

We study a $D$-dimensional Einstein-Gauss-Bonnet model which includes the Gauss-Bonnet term, the cosmological term $\Lambda$ and two non-zero constants: $\alpha_1$ and $\alpha_2$. Under imposing the metric to be diagonal one, we find cosmological type solutions with exponential dependence of three scale factors in a variable $u$, governed by three non-coinciding Hubble-like parameters: $H \neq 0$, $h_1$ and $h_2$, obeying $m H + k_1 h_1 + k_2 h_2 \neq 0$, corresponding to factor spaces of dimensions $m > 1$, $k_1 > 1$ and $k_2 > 1$, respectively, and depending upon sign parameter $\varepsilon = \pm 1$, where $\varepsilon = 1$ corresponds to cosmological case and $\varepsilon = - 1$ - to static one). We deal with two cases: i) $m < k_1 < k_2$ and ii) $1< k_1 = k_2 = k$, $k \neq m$. We show that in both cases the solutions exist if $\varepsilon \alpha = \varepsilon \alpha_2 / \alpha_1 > 0$ and $\alpha \Lambda > 0$ satisfies certain (upper and lower) bounds. The solutions are defined up to solutions of certain polynomial master equation of order four (or less) which may be solved in radicals. In case ii) explicit solutions are presented. In both cases we single out stable and non-stable solutions as $u \to \pm \infty$. The case $H = 0$ is also considered.

To study the conditions of thermal equilibrium of relativistic electron beam (REB) is important for numerous fundamental and applied tasks of accelerator physics and space physics as well as physical electronics. In our report the analytical study of the dynamics of neutralized relativistic electron beam is presented. The beam parameters are found which correspond to equilibrium propagation of a beam characterized by arbitrary 4D-phase configuration in a long-pulse approximation. The results obtained allow to shape the equilibrium REB as well as to predict the behaviour of a beam in a wide range of initial beam parameters.

The study of primary cosmic rays is usually carried out by either direct measurements by means of satellite detectors or indirect measurements by ground-based detectors of secondary particles generated in extensive air showers (EAS). The main types of ground-based installations are scintillator or Cherenkov detectors that register light from all particles that give ionization in their working volume. Such detectors are distributed over large area and the amplitude and time of their response give a direction and a size of EAS. Such setup is implemented in experimental complex NEVOD in MEPhI. It is based on scintillator detectors and covers an area of 104 m2.
Classical EAS setup can be supplemented by coordinate-tracking detector that can separate particle tracks and measure their number and direction. The new coordinate-tracking detector ProtoTREK based on multiwire drift chambers is developed in MEPhI. It has an area of 13 m2 and can measure up to 15 particles per m2. Such setup can act like a valuable additional detector of primary cosmic rays. Monte-Carlo simulation shows that coordinate-tracking detector can give an independent information on EAS. The first comparison of ProtoTREK and NEVOD-EAS response shows a compliance. This new approach to EAS investigations is described.

The article considers geo-effective phenomena that arose in near-Earth outer space and on Earth during 23 and 24 cycles of solar activity. The results of the SWPC NOAA data processing showed that about 90% of proton events with an energy of $p_T > 100$ MeV and 100% of terrestrial increases (GLE) are associated with solar flares with a capacity of more than M5.0. Methods of operational prevention of high-energy proton flows in near-Earth orbit are considered. As indicators, it is proposed to jointly monitor soft X-rays in the range of 0.1- 0.8 nm and protons with $p_T > 100$ MeV. Characteristics of associated active regions (AR) on solar hemisphere are considered for prediction of GLE. The types of the most effective ARs and their peculiarities of development before a geo-effective solar flare are identified. One-day GLE forecast procedure for AO monitoring was proposed and its effectiveness and success were evaluated.

The spectroscopy of higher lying charmonium states together with exotic mesons with masses above the $2\,m(D)$ open charm threshold has been full of surprises and remains poorly understood [1]. It is a good testing tool for the theories of strong interactions, including: QCD in both the perturbative and non-perturbative regimes, LQCD, potential models and phenomenological models. The experiments with antiproton-proton annihilation, proton-proton and proton-nuclei collisions are well suited for a comprehensive spectroscopy program, in particular, the spectros-copy of chamonuim and exotics states.
The currently most compelling theoretical descriptions of the mysterious XYZ mesons attrib-ute them to hybrid structure with a tightly bound diquark [2] or tetraquark core [3 - 5] that strongly couples to S-wave molecular like structures. In this picture, the production of a XYZ states in high energy hadron collisions and its decays into light hadron plus char-monum final states proceed via the core component of the meson, while decays to pairs of open-charmed mesons proceed via the component.
These ideas have been applied with some success to the XYZ states [2], where a detailed calcu-lation finds a core component that is only above 5% of the time with the component (mostly) accounting for the rest. In this picture these states are compose of three rather disparate components: a small charmonium-like core with rrms < 1 fm, a larger component with rrms $\approx 1.5$ fm and a dominant component with a huge, rrms ≈ 9 fm spa-tial extent.
In the hybrid scheme, XYZ mesons are produced in high energy proton-nuclei collisions via its compact (rrms < 1 fm) charmonium-like structure and this rapidity mixes in a time ($t\sim\hbar/\delta M$) into a huge and fragile, mostly , molecular-like structure. $\delta M$ is the difference between the XYZ mass and that of the nearest mass pole core state, which we take to be that of the $\chi c1(2P)$ pure charmonium state which is expected to lie about $20\sim30$ MeV above m(X(3872)) [6, 7]. In this case, the mixing time, cτmix $5\sim10$ fm, is much shorter than the lifetime of X(3872) which is $\chi\tau X(3872) > 150$ fm [8].
The near threshold production experiments in $\sqrt{s}_{pN}\sim 8$ GeV energy range with proton-proton and proton-nuclei collisions with$\sqrt{s}_{pN}$ up to 26 GeV and luminosity up to $10^{32}cm^{-2}s^{-1}$ planned at NICA may be well suited to test this picture for the X(3872) and other exotic XYZ mesons [9]. Their current experimental status together with hidden charm tetraquark candidates and present simulations what we might expect from A-dependence of XYZ mesons in proton-proton and proton-nuclei collisions are summarized.

References

[1] S. Olsen, Front. Phys. 10 101401 (2015)

[2] S. Takeuchi, K. Shimizu, M. Takizawa, Progr. Theor. Exp. Phys. 2015, 079203 (2015)

[3] A. Esposito, A. Pilloni, A.D. Poloza, arXiv:1603.07667[hep-ph]

[4] M.Barabanov, A.Vodopyanov, S.Olsen, A. Zinchenko, Phys. Atom. Nuc. 79, 1, 126 (2016)

[5] M. Barabanov, A. Vodopyanov, Study of Charmonium-Like Structure in Hadron and Heavy Ion Collisions, Physics of Atomic Nuclei, V. 84, N. 3, (2021) 373–376

[6] Isgur, Phys. Rev. D 32, 189 (1985)

[7] K. Olive et al. (PDG), Chin. Phys. C 38, 090001 (2014)

[8] The width of X(3872) is experimentally constrained to be Г X(3872) < 1.2 (90% CL) in S.-K. Choi et al (Belle Collaboration), Phys. Rev. D 84, 052004 (2011)

[9] M. Barabanov, J. Segovia, C.D. Roberts, E. Santopinto et al., "Diquark correlations in hadron physics: origin, impact and evidence", Progress in Particle and Nuclear Physics 116 (2021) 103835

The characteristics of detectors made of silicon carbide (SiС) irradiated with various integral fluxes of both Xe ions with an energy of 165 MeV and fast neutrons were studied. With the help of alpha-particles, it was found that the energy resolution of SiC detectors irradiated with the maximum fluxes of heavy ions ($F_{max} = 2.3\times10^9$ ion/cm$^2$) and neutrons ($F_{max} = 3.4\times10^{15}$ n/cm$^2$) deteriorates by an order of magnitude. It was shown that the efficiency of detector charge collection decreases to 2 and 50%, respectively, upon irradiation with Xe ions and neutrons.

Placement of the hydroacoustic antenna-detector for ultrahigh energy neutrino
directly below the underwater acoustic channel gives several important advantages.
They simplifies the creation of the phased hydroacoustic array and signal processing for registration of such neutrinos. High temperature of the Mediterranean in comparison with other seas improves detector sensitivity. Placement of the acoustic channel at small depth simplifies the underwater equipment design.

Double electron-capture (EC/EC) of $^{58}$Ni on excited states of $^{58}$Fe is investigated at Baksan neutrino observatory INR RAS in DULB-4900 laboratory (4900 m w. e.) using the ultralow-background HPGe detector with a sensitive volume of 200 cm$^3$ ($\sim1$ kg mass) and a natural nickel sample of $\sim68$% $^{58}$Ni with a mass of $\sim 6$ kg. The detector is surrounded by low-background shield consist of 180 mm oxygen-free copper, 150 mm lead, 1 mm cadmium and 80 mm polyethylene. After preliminarily analysis of the experimental data accumulated over 3200 hours, the experimental limits are obtained for the 2νEC/EC decay of $^{58}$Ni to the 2$^{+}_{1}$, 811 keV and 2$^{+}_{2}$, 1675 keV excited states of $^{58}$Fe. The limits are T$_{1/2}$ (EC/EC, 0 → 2$^{+}_{1}$) > 4$\cdot$10$^{21}$ yr, and T$_{1/2}$ (EC/EC, 0 → 2$^{+}_{2}$) > 7$\cdot$10$^{21}$ yr. At the same time, the sensitivity of the experimental setup for one year of measurements to the processes mentioned above is: S (EC/EC, 0 → 2$^{+}_{1}$) = 2$\cdot$10$^{22}$ yr, and S (EC/EC, 0 → 2$^{+}_{2}$) = 1.3$\cdot$10$^{22}$ yr. All limits are at 90% CL.

When the temperature of the pyroelectric single crystal changes, X-ray generation is possible. To obtain the above effect, it is necessary to change the temperature of the crystal in vacuum (pressure on the order of several mTorr). Under such conditions, an electric field arises between the grounded target and the crystal surface, which causes the field emission of electrons from the crystal surface [1]. This opens up prospects for using pyroelectric crystals as compact electron accelerators. An accelerator based on a lithium tantalate $(LiTaO_3)$ crystal with a surface charge of 1200 nC is capable of generating electron beams with an energy of about 20 keV.

It was shown in [2] that due to the non-uniform charge distribution on the pyrocrystal surface, the electric field lines converge at one point. This feature allows us to suggest the possibility of the presence of the self-focusing effect in the pyroaccelerator. This hypothesis was tested using numerical simulation based on the finite element method.

It was assumed that the emission occurs from the surface of the crystal. The simulation results confirmed the self-focusing hypothesis. The dependence of the maximum electron energy on the emission point and the focal length on the radius on the crystal surface are obtained. The electron spectrum obtained is consistent with the experiment.

The simulation made it possible to elucidate the radiation characteristics, which are difficult to find experimentally. The model was verified. The trajectories of electrons and their energies agree well with experiment and theory. The theoretically predicted non-uniform charge distribution and self-focusing are confirmed. Simulated monoenergetic electron flow in a pyroelectric accelerator can be used for calibrations of different particle detectors facilities.

The work was supported by the grant from the Russian Science Foundation (project №21-72-00006).

[1] Kubankin A. S. et al. Optimal speed of temperature change of a crystal in a pyroelectric X-ray radiation source // AIP Advances. 2018.

[2] Ghaderi R., Davani F. A. Determination of surface electric charge profile in pyroelectric crystals // Applied Physics Letters. 2014.

In recent decades, Cherenkov water (ice) telescopes such as IceCube, Baikal-GVD and KM3Net have been actively developed for research in the field of neutrino physics and astrophysics. Optical modules are the main detecting elements of such neutrino telescopes.
Calibration of optical modules of different neutrino telescopes under the same conditions is one of the important experimental problems. Such a calibration can be carried out at the Experimental complex NEVOD. Scientific installations of the complex make it possible to identify tracks of single near-vertical and near-horizontal muons, as well as to detect events with large energy deposits and to study the response of the optical module being tested to these events.
In the report, we discuss the software and hardware complex for calibrating optical modules of Cherenkov neutrino telescopes at the Experimental complex NEVOD, as well as the possibility of its implementation for studying the characteristics of the Baikal-GVD optical module.

A.T. D’yachenko$^{1,2}$, M.S. Abu-Khasan$^{2}$

$^{1}$ National Research Center “Kurchatov Institute” B.P. Konstantinov Petersburg Nuclear Physics Institute, Gatchina, Russia:

$^{2}$ Emperor Alexander I Petersburg State Transport University, St. Petersburg, Russia

Within the framework of our approach, we have found an analytical solution of the equations of hydrodynamics in the soliton approximation for the collision of layers in the one-dimensional and two-dimensional cases. The contraction stage, the expansion stage, and the expansion stage are considered within the framework of a single formula for layers with energies on the order of ten MeV per nucleon. Such a reduction of solutions of hydrodynamic equations to soliton solutions has not been considered before.
The introduction of dispersion into the effective forces and into the pressure does not violate the concept of the formation of a hot spot. The introduction of additional dimensions does not violate this representation. Here we develop an approach to the approximate analytical solution of these equations, both in the case of weak nonlinearity, by reducing them to the Korteweg-de Vries equations, and in the case of large-amplitude perturbations, using soliton-like solutions.
Our generalization to the two-dimensional case leads to the idea of the formation at the stage of expansion of a rarefied region-bubble, the search for which is the subject of long-standing research. And the approach itself is of independent interest and can be used in other areas of physics and technology when calculating the nonlinear dynamics of oscillations of complex systems. In our works [1-4], it was shown that the local thermodynamic equilibrium in the process of collisions of heavy ions is not established immediately.
The nonequilibrium approach to hydrodynamic equations makes it possible to describe experimental data better than the equation of state corresponding to traditional hydrodynamics, which assumes the establishment of local thermodynamic equilibrium.

1.A.T. D'yachenko, K.A. Gridnev, W. Greiner, J. Phys. G40, 085101 (2013)

2.A.T. D'yachenko, I.A. Mitropolsky, Phys. Atom. Nucl. 83, 558 (2020).

3.A.T. D'yachenko, I.A Mitropolsky, Bull. Russ. Acad. sci. Phys. 84, 391 (2020).

4.A.T. D'yachenko, I.A.Mitropolsky, Bull. Russ. Acad. sci. Phys. 86 , 962 (2022).

In spite of the fact that nuclear track emulsion (NTE) was developed more half a century ago, it still remains a universal and cost-efficient detector. The application of NTE is especially well grounded where tracks of nuclear particles cannot be reconstructed using electronic detectors. At the JINR Nuclotron the BECQUEREL experiment [1] is performed a program of irradiation of NTE stacks in the beams of relativistic isotopes of beryllium, boron, carbon and nitrogen, including radioactive ones to study their cluster structure. Сharge-topology distributions of final states have an individual character appearing to be some kind of a signature of the isotope under study. The NTE technique allows one to observe the 3D images of few-body ensembles originated in peripheral collisions and explore the fragmentation of the relativistic nuclei down to the most peripheral interactions - nuclear “white” stars [2].
The competitive character of the novel NTE is proved in measurements of slow α particles and heavy ions (summarized in [3]). The possibility of α spectrometry was verified and the atom drift effect is established in measurement of decays of 60 MeV 8He nuclei implanted in NTE [4]. Correlations of α particles in splitting of 12C nuclei by 14.1 MeV neutrons [5] as well as 7Li and 4He nuclei produced in 10B breakup by thermal neutrons in boron-enriched NTE [6] are studied. NTE samples were irradiated with slow Kr and Xe ions [7,8]. Surface irradiations of NTE samples were performed with automatic movement of the 252Cf source [9].
Recently, samples of reproduced NTE were also irradiated with 2.5 and 160 GeV muons (started in [10]). Such irradiation allows one to study few-body fragmentation under the action of an electromagnetic probe [11]. Multiphoton exchange or virtual photon–meson transformations can serve as the fragmentation mechanisms. It was established that the breakup of carbon nuclei into trios of α particles has a nuclear diffraction rather than electromagnetic character. Thus, the connection of high energy and low energy nuclear physics appears.
Classic observations of fundamental importance presented in “The Study of Elementary Particles by the Photographic Method” by C. H. Powell, P. H. Fowler and D. H. Perkins can serve as a model of clarity in our time. Our research is implemented in keeping with this tradition by state-of-art means. The rich collection of videos and images of the nuclear few-body processes gathered at the Web site is presented [1]. In terms of applications they are relevant for the development of advanced systems of automatic search for nuclear interactions, as well as for university education.

References

1. The BECQUEREL Project WEB site: http://becquerel.jinr.ru/

2. http://becquerel.jinr.ru/movies/movies.html

3. P. I. Zarubin “Recent applications of nuclear track emulsion technique” Phys. At. Nucl., 2016, 79, 1525-1535; DOI: 10.1134/S1063778816130093.
   https://link.springer.com/article/10.1134/S1063778816130093

4. http://becquerel.jinr.ru/miscellanea/8He/8He.html

5. http://becquerel.jinr.ru/miscellanea/DVIN/dvin11.html

6. http://becquerel.jinr.ru/miscellanea/IBR-2/IBR-2.html

7. http://becquerel.jinr.ru/miscellanea/IC-100/IC-100.html

8. http://becquerel.jinr.ru/miscellanea/U400M/U400M.html

9. http://becquerel.jinr.ru/miscellanea/Prague-dosimetry/Prague-dosimetry.html

10. D. A. Artemenkov et al. “Study of nuclear multifragmentation induced by ultrarelativistic μ-mesons in nuclear track emulsion” J. Phys.: Conf. Ser. 675 022022.
    http://iopscience.iop.org/article/10.1088/1742-6596/675/2/022022

We study deuteron- proton elastic scattering in the GeV energy range.
Nowadays, a significant amount of the experimental data at these energies
has been accumulated both with unpolarized and polarized beams. However,
a theoretical description of the data faces problems because of
well developed Faddeev calculation technique cannot be applied at these energies.

In this report we consider deuteron- proton elastic scattering in the
relativistic multiple scattering expansion framework. The following reaction mechanisms are included into consideration: one-nucleon exchange, single scattering, and double scattering. Also, the term corresponding to the delta excitation in the intermediate state is taken into account. This model
is applied for a description of the experimental data both on the differential cross section and polarization observables in a whole angular range.
The obtained theoretical predictions are compared with the existing experimental data. Effects of the different reaction mechanisms are analyzed.

Scientific project GAMMA-400 relates to the new generation of space observatories intended to perform a search for signatures of dark matter in the cosmic gamma emission, measurements of characteristics of diffuse gamma-ray emission and gamma-rays from the Sun during periods of solar activity, gamma-ray bursts, extended and point gamma-ray sources, electron/positron and cosmic-ray nuclei fluxes up to TeV energy region by means of GAMMA-400 space-based gamma-ray telescope represents the core of the scientific complex. The main results obtained using ~300 MeV positron beam of synchrotron C 25P “PAKHRA” of Lebedev Physical Institute with prototypes of time of flight and anticoincidence system of gamma-ray telescope are presented. The amplitude resolution, time resolution and charged particles detection efficiency are adduced. The comparison of using both «slow» and «fast» outputs of silicon photomultipliers of prototype scintillation detectors sensors is featured.

Newtonian dualism of localized material bodies with delocalized fields of interaction in non-material space contradicts the monistic all-unity of material space in Russian Cosmism. Its Cartesian physics with the Umov vector for energy transports in the material continuum predicts a monotonous decrease in the transmission of information and light power under a rarefaction of the cosmic medium-space. On the contrary, the Newtonian worldview of particles and their remote or field interactions predicts a monotonous increase in light power and information transfer rate in rarefied regions of the space-arena due to a decrease in scattering. A calibrated laser power transfer in variable vacuum in laboratory tubes or in the upper atmosphere can falsify (by precision measurements) the particle-field dualism in the Standard Model of Physics in favor of monistic field matter.

We study the one-parameter generalizations of the Starobinsky model of inflation, which obey all observational constraints on the inflationary parameters. Our models are connected to the original Starobinsky model via continuously changing an additional parameter. Modifying the Starobinsky $R+R^2$ inflationary model by adding an $R^{3/2}$-term, we find that the tensor-to-scalar ratio significantly increases with raising the parameter in front of that term. The talk is based on the paper V.R. Ivanov, S.V. Ketov, E.O. Pozdeeva and S.Yu. Vernov, JCAP 03 (2022) 058 and recent investigations.

Within the framework of the variational method in quantum electrodynamics, the energy levels of bound states of three particles muon-electron-nucleus with light nuclei are studied. The calculation uses a Gaussian basis for trial wave functions. The electron and muon Lamb shifts in such three-particle systems are calculated.

Axion is a hypothetical pseudoscalar Nambu-Goldstone boson that was introduced as an extension to the Standard Model intended to solve the strong CP problem.
It also could be a possible solution for a series of other fundamental physics problems such as the the dark matter or photon ultratransparency of the Universe.
As the least model-dependent axion interaction is its interaction with a nuclei, the most promising reaction for axion search is the resonant absorption.

If an axion exists, the sun would be a strong source of axion radiation, produced by mainly the so-called ABC reactions (Atomic recombination and deexcitation, Bremsstrahlung and Compton). These reactions produce axions with energies in the keV range and thus their detection through resonant absorption requires a nuclide with low-energy magnetic type gamma-transition. An optimal nuclide fulfilling these requirements is $^{169}$Tm that has an M1 transition with energy of 8.41 keV with magnetic type transition fraction that could be estimated close to unity.

In this work we describe a novice technique of axion search with Tm-containing crystal $\rm{Tm}_3\rm{Al}_5\rm{O}_{12}$, a garnet that could be operated in the bolometric regime. A small sample of this crystal of 8.18 g has been already applied for axion search producing a new limit of the coupling constants: $|g_{A\gamma} (g^0_{AN} + g^3{AN} )| \leq 1.44 \times 10^{−14} GeV^{−1}$ and $|g_{Ae}( (g^0_{AN} + g^3{AN} )| \leq 2.81 \times 10^{−16}$.

The multipomeron exchange model was considered earlier in papers [1 – 5]. Within the framework of this model, it was possible to successfully describe the charged multiplicity (Nch), mean transverse momentum (pt) and pt-Nch correlations in pp and pp¯ collisions over a wide energy range (from ISR to LHC). It allowed also to reproduce the growth of the yields of strange, multi-strange and charm particles as a function of multiplicity for pp, p-Pb and Pb-Pb collisions at the LHC energy. For this, in particular, the general idea of the Schwinger mechanism of particle production from a string [6] was used, where the transverse momentum distribution of charged particles from a string has a Gaussian form, and in case of string overlap the effective string tension was related to the number of strings. However, experimental data show that the pt-spectra of particles produced in pp collisions are better described by the thermal model. To solve this problem, we introduced the thermal-like pt distribution function which can be considered as averaging out over string tension fluctuations [7]. We calculated pt-spectra and pt-Nch correlations functions for pp-collisions at the LHC energy in extended multipomeron exchange model and compared the results with the experimental data.

The research was supported by the SPbSU project, No 93025435.

1. Armesto N., Derkach D.A., Feofilov G.A. p(t)-multiplicity correlations in a multi-Pomeron-exchange model with string collective effects. Phys. Atom. Nucl. 2008, 71, 2087–2095.
2. Bodnia E., Derkach D., Feofilov G., Kovalenko V., Puchkov A. Multi-pomeron exchange model for pp and pp¯ collisions at ultra-high energy. PoS QFTHEP2013 2013, 60.
3. Kovalenko V.N., Puchkov A.M., Feofilov G.A. Production of strange particles in a multi-pomeron exchange model. Bull. Russ. Acad. Sci. Phys. 2016, 80, 966–969.
4. Feofilov G., Kovalenko V., Puchkov A. Correlation between heavy flavour production and multiplicity in pp and p-Pb collisions at high energy in the multi-pomeron exchange model. EPJ Web Conf. 2018, 171, 18003.
5. Kovalenko V., Feofilov G., Puchkov A., Valiev F. Multipomeron Model with Collective Effects for High-Energy Hadron Collisions. Universe 2022, 8, 246. https://doi.org/10.3390/universe8040246
6. Schwinger J.S. On gauge invariance and vacuum polarization. Phys. Rev. 1951, 82, 664–679.
7. Bialas A. Fluctuations of the string tension and transverse mass distribution. Phys. Lett. B 1999, 466, 301–304.

Phase structure of dense quark matter with chiral and isospin imbalance is considered in the framework of effective models. There has been considered as two color as well as three color QCD. It was shown that chiral imbalance has several rather peculiar properties such as being universal catalyzer,
i. e. it catalyzes all the considered symmetry breaking patterns in the system, including the diquark condensation phenomenon (color superconductivity). Duality properties found earlier have been considered in both case.
It was shown that the phenomenon of color superconductivity, which dominates at
high baryon density, does not suppress the previously known effect that the chiral the imbalance leads to charged pion condensation in a dense quark medium, i.e. quark medium with nonzero baryon density.
It was investigated how the chiral imbalance affects the phase of the color
superconductivity. It has been shown that chiral imbalance leads to the appearance phases of color superconductivity in dense quark matter at lower
values ​​of baryon chemical potentials than in a chirally symmetric medium. It
may have some interesting implications for collision experiments
heavy ions with medium energies (at moderate energy heavy ion collisions).

Based on:
Phys.Rev.D 106 (2022) 4, 045008
JHEP 06 (2020) 148
Eur.Phys.J.C 80 (2020) 10, 995

Particle identification at the Super Charm-Tau factory experiment will be provided by a Focusing multilayer Aerogel
ring imaging Cherenkov detector FARICH. Due to hardware constraints the detector captures a great amount of noise
which must be mitigated to reduce both a data flow and further storage space.
In this presentation we present our approach to filtering signal hits. The approach is inspired by object detection
techniques for computer vision. Several ML based approaches to the FARICH reconstruction problem in different settings
are also discussed.

The existence of dark matter has been discussed for more than a century. Today we have a compelling body of evidence for this elusive component of the Universe, based on a variety of observations, at different scales, but no experiment has detected dark matter yet. This talk will focus on direct detection of dark matter.
The null result of both direct detection and LHC searches has produced a paradigm shift in the community that is now expanding the hunt to cover 90 orders of magnitude in mass. Current and next generation of detectors will push the sensitivity for WIMPs - the strongest dark matter candidate since the 1980s - down to the neutrino floor. In particular the physics case of different dark matter direct detection experiments will be presented and the different and complementary techniques which are being applied or considered will be discussed, summarizing their features and latest results obtained. A special focus will be made on TPC-related projects; experiments using noble liquids have presently a leading role to constrain interaction cross sections of a wide range of dark matter candidates and gaseous detectors are very promising to explore specifically low mass dark matter as well as to measure directionality.

A summary what we have obtained with Borexino

Neutrino is considered as an ideal astronomical messenger thanks to not being deflected or absorbed by interstellar medium. Detection of neutrinos from distant high-energy cosmic accelerators has been a long-standing problem emerged in the last quarter of the 20-th century. And only in 2013 was the diffuse cosmic neutrino flux discovered by the 1 km3 -scale IceCube neutrino telescope at the South Pole. Nevertheless sources of cosmic neutrino remain unknown up to the present day. The Baikal-GVD neutrino telescope being built in the Lake Baikal is the largest detector of this kind in the Northern Hemisphere. Presently an instrumented volume of the detector reaches ~0.5 km3 which allows the telescope to start contributing to the cosmic neutrino origin quest. In this talk we give an overview of high-energy neutrino astronomy and discuss the status and main results of the Baikal-GVD experiment.

A review and status of neutrino oscillations studies from long baseline accelerator based experiments will be presented. An emphasis will be placed on recent results from running experiments such as T2K and NOvA. In addition the status plus plans of future experiments DUNE and HyperK will also be discussed.

The process of double Compton scattering, $e \gamma \to e \gamma \gamma$,
in strongly magnetized charge-asymmetric, cold electron plasma is considered.
The amplitude of the process is obtained and
selection rules for photon polarizations are found.
It is shown that in such a plasma the process of double Compton scattering will be
efficient mechanism for the production of polarized photons.
As a result, it could lead to the modification in the mechanism of
the spectra formation of SGR and AXP.

In this work we consider hypothetical decay of a dark matter particle into two positrons with final state radiation (FSR): $X^{++}\rightarrow e^{+} e^{+} \gamma$. We investigate possibility of FSR suppression with respect to the analogous decay of $X^{++}\rightarrow e^{+} e^{-} \gamma$ in quantum mechanical case. This is done with the use of MC generators. Such suppression would help explaining positron anomaly in cosmic rays, where accompanying gamma radiation contributing to isotropic gamma-ray background (IGRB) leads to a contradiction. Such suppression is to be expected due to the so-called “single-photon theorem”, which connects the quantum mechanical case to the classical one, where such a radiation is simply nonexistent. Our results show that suppression indeed does occur and intensifies with an increase of photon energy, which should assist in resolving the above-mentioned contradiction.

The present status of the experiment PHELEX on the search for dark photons with a multi-cathode counter is presented. The improved upper limit for a constant of kinetic mixing has been obtained. The importance of measuring the diurnal variations of count rate to prove that dark photons be really observed is shown. First results of diurnal variations have been obtained. New design of multi-cathode counter is presented. The results obtained are discussed and the task for a further study is formulated.

The mantle -- a layer of nonspherical (pasta-like) nuclear shapes -- can exist in neutron stars and play an important role in their dynamics and evolution. We analyze accuracy of the Compressible Liquid Drop Model (CLDM), based on the thermodynamically consistent description of the surface properties calculated for the two-phase plane interface for given energy-density functional (for numerical illustration, we apply Skyrme-type functional SLy4). For this aim we compare CLDM results with direct calculation of the pasta phases within Extended Thomas-Fermi (ETF) method. Our ETF calculations found a significant mantle layer, consisting of the pasta phases in cylindrical form (both normal and inverse phases, aka spaghetti and bucatini). Meanwhile, within the applied CLDM framework, which neglects curvature corrections, the inverse phases are absent while the spaghetti phase was found to be energetically favourable only in the small density range prior to crust-core transition. On the other hand, the recent CLDM of Dinh Thi et al. 2021, which, on the opposite, accounts for curvature term predicts pasta phases in better agreement with the ETF, however this model neglects thermodynamically required effect of neutron adsorption and employs additional data to describe the surface properties. This fact highlights the importance of the curvature effects in analysis of the pasta properties within CLDMs.
This research was funded by Russian Science Foundation, grant number 22-12-00048.

The solution of the kinetic equation for finding the distribution function of photons of two possible polarizations in an equilibrium e+e- plasma in a relatively strong magnetic field in the cold plasma approximation and taking into account
resonance on a virtual electron is considered. Using the Laplace transform and sum of the distribution function in terms of Legendre polynomials, the problem is reduced to a system of differential equations, the coefficients of which can be easily calculated numerically.

The muon puzzle has been one of the most intriguing problems in cosmic ray physics over the past few years. The contradiction between the experimental data and simulation results suggests the presence of physical processes that go beyond the framework of contemporary hadronic interaction models. One of these approaches is based on the hypothesis that strongly polarized blobs of quark-gluon plasma which decay to heavy particles are formed in non-central nucleus-nucleus collisions. In this work, the influence of the production of these heavy particles on the EAS development, μ/e-ratio and measured shower energy is considered.

Based on the relativistic constraint technique[1] for the Dirac equation in the two-particles problem[2] positronium states in a strong uniform magnetic field are studied. The width of the singlet positronium state in such conditions is obtained in the explicit form. It is shown that the magnetic field sufficiently increases the decay width, comparing with the case of a free positronium. The positronium collapse[3] in the extremely strong magnetic fields is discussed.

[1] A. M. Dirac, Lectures on Quantum Mechanics (Yeshiva
University, Belfer Graduate School of Science, New York,
1964).

[2]H.W.Crater, P. van Alstine, Phys. Rev.D , v.36, 3007 (1987).

[3]A.E.Shabad, V.V. Usov, Phys. Rev. Lett., v.96, 180401 (2006).

Dark matter lighter than 10 GeV/c2 encompasses a promising range of candidates. The new analysis of the entire dataset acquired with a low-radioactivity argon target by the DarkSide-50 experiment at LNGS is presented. The new analysis benefits from more accurate calibration of the detector response, improved background model, and better determination of systematic uncertainties. A conceptual design for a new detector, DarkSide-LowMass, is proposed, based on the DarkSide-50 detector results, optimized for a low-threshold electron-counting measurement. Sensitivity to light dark matter is explored for various potential energy thresholds and background rates. The studies show that DarkSide-LowMass can achieve sensitivity to light dark matter down to the solar neutrino floor for GeV-scale masses.

The shape of redshift distribution for uniform sources set in our Metagalaxy defined by cosmological parameters and properties of space. The type Ia supernovae usually considered as a homogeneous subsample because of suggestion that these luminous events could be used as standard candles for cosmological measurements. This mention occurs since the earliest studies of supernovae in 1938. Firstly the parameters of our Metagalaxy Ω and Λ were determined due sample of Ia supernovae from the Supernova Cosmology Project analysis in 1998. It was found due SN1a characteristics investigation that space in our Metagalaxy is Euclidean at small redshifts and de-Sitter at high ones. Now several tens of thousand supernovae’ characteristics analyzed in new catalogues. The preliminary results of the redshift distribution investigation for SNIa from the Asiago
Supernova and Open Supernova Catalogues are discussed in this work. Firstly it was
shown that several peculiarities are presented in Ia supernovae redshift distribution in both objects subsamples. The deviation in the band 0.015 < z < 0.13 accordingly Open Supernova Catalogue (OSC)
data contain more faint supernovae. Two peculiarities also were found in the region 0.25 < z < 0.45 on data of this catalogue. One of it’s contain more faint events, other
contain more bright supernovae. The separated peculiarities and areas could not be explained due 2 groups of type
Ia SNe explosions scenarios and dimming of flux due interaction of surrounding media. Thus such peculiarities presence could be caused by several unknown aspects of SNIa
explosions scenarios or really changing of the parameters of our Metagalaxy. Further conclusions
required subsequent OSC database treatment in combination with high redshift
datasets, for example, addition of Dark Energy Survey Supernova Program catalogue
into data analysis.

Preliminary results of the investigation of the properties of 13 clusters of galaxies from CfA2 redshift survey are discussed in the presented article. The distributions on absolute magnitude and luminosity represent two areas for clusters ##88, 1101, 1046, 142, 933, 1242, 1652, 107, 150, 316, 317, 961, 977. Redshifts of these clusters are in the region 0.002 – 0.032. Also several anomalies of spatial dynamic of galaxies in these clusters were separated. Clusters #933, #142, #1046, #1652 and #316 reveal high-energy $\gamma$-associations on Fermi/LAT 12-Year Point Source Catalog 4FGL-DR3 (4FGL J1144.9+1937, 4FGL J0152.2+3714, 4FGL J1230.8+1223, 4FGL J1653.8+3945 and 4FGL J0708.9+4839). Moreover, sources 4FGLJ1144.9+1937 and 4FGLJ1230.8+1223 observed in subTeV energy band by VERITAS data.
Than we have investigate these systems dynamic using Nonlinear Time Series Analysis. We have construct phase space for such clusters of galaxies using values of redshift, coordinates, magnitude, absolute magnitude and distance to centre. As timelike variable we supposed the ratio between galaxies tangential velocity and its distance to cluster's centre. Accordingly to preliminary results of analysis we have obtained two attractors in the phase space of cluster #88 and ones with presence of high-energy gamma-emission with basins corresponds to bifurcation points on the analyzable distributions. Such results concludes real dual structure of systems being studied. The presence of such structure allows conclude two alternatives. In the first one dark matter presence inside cluster or its the nearest neighbourhood in configuration similar to Zeldovich pancake. Second case is gravitational lensing on compact object or dark matter blob located between galaxy cluster and observer.
Joint observations of such clusters by orbital gamma-ray observatories with high angular resolution and ground-based Cherenkov air-shower experiments could possibly clarify the type of influence to groups characteristics (gravitational lensing or object inside cluster) and processes of particle acceleration in these objects especially highest energy of emitted gammas. Thus we propose including these clusters and similar objects in the programs of observations of the planned experiment GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) with angular resolution ∼ $\sim 0.01^o$ at Eγ = 100 GeV and upper energy band boundary about several TeV. Also now the coordination of multiwavelength observations program of Cherenkov Telescope Array (CTA) and GAMMA-400 is discussed.

The intrinsically large variation of the energy deposited in a calorimeter by hadrons imposes limitations on the improvement of hadron energy resolution. The fluctuation of electromagnetic fraction within a hadronic shower is known to be one of the main sources of such variations. Several techniques were developed to improve the energy resolution for hadrons including the so called hardware compensation (compensating and dual-readout calorimeters) and software compensation approaches. The reliable prediction of the amount of electromagnetic fraction on an event-by-event basis opens a possibility to correct the energy during the offline reconstruction and improve the energy resolution. In this study, the samples were investigated of hadronic showers simulated with physics lists from Geant4 package version 10.3 in the model of a highly granular hadron calorimeter for the initial hadron energies 10--80 GeV. The deep neural network was trained using a supervised learning and calorimetric observables as inputs to predict the electromagnetic fraction in a shower. The achieved neural network performance and observed improvement in hadron energy resolution of more than 15% are presented and discussed.

The technology of highly granular calorimeters is one of the main innovations that will be implemented in planned experiments on future colliders. This work shows an algorithm for the improvement of energy resolution in highly granular calorimeters based on a machine learning technique. An artificial neural network, which helps to connect calorimeter observables, was trained and tested. The study was performed on a simulated version of the detector with highly granular calorimeters for single hadrons with energies from 1 to 120 GeV.

M.Bhattacharjee1,3, S.A.Bulychjov2, Yu.F.Krechetov1, V.V. Kulikov2,
M.A. Martemianov2, M.A. Matsyuk2, I.A. Tyapkin1
1 Joint Institute for Nuclear Research, 141980, Dubna, Russia
2 National Research Center “Kurchatov Institute”, Moscow, 123182 Russia
3 Gauhati University, Guwahati, Assam 781014, India
In a framework of the NICA/MPD project [1], a cylindrical electromagnetic calorimeter (ECal) [2] with an internal(external) diameter of 3.45 (4.6) m , a length of 6 m and a total weight of about 60 tons is under construction. The calorimeter consists of 38,400 “shashlik”-type towers with 210 alternating layers of a 1.5 mm scintillator and 0.3 mm lead coated with reflective paint. The shapes of the towers are of 64 types. Approximately they are truncated pyramids with a base of 4x4 cm2, height of 41 cm and vertex angles of 0.9 and 1.2 degrees in the longitudinal and transverse plane relative to the cylinder axis. ECal implements the so-called projective geometry when the axes of all towers look at one point - the intersection point of the collider beams located in the center of the cylinder. Every 16 towers are combined into 2400 modules of 8 types. Large number of modules have been already produced [3] and tested on electron beams and cosmic rays [4,5]. In this report we discuss the energy calibration procedure with cosmic muons with the main emphasis on its accuracy and corrections needed for different types of the towers and their orientation in space. The results are based on MC simulation and comparison with the existing measurements.
[1] The MPD Collaboration: V. Abgaryan et al. «Status and initial physics performance studies
of the MPD experiment at NICA. Eur.Phys.J.A 58 (2022) 7, 140.
[2] V.V. Kulikov et al. ECal MPD: geometry and simulation. 2020 JINST 15 C09017. [3] Y. Li et al. Production and quality control of NICA-MPD shashlik electromagnetic calorimeter
in Tsinghua University. JINST 17 (2022) 04, T04005.
[4] V.A. Baskov et al. Electron Beam Test of the MPD Electromagnetic Calorimeter on the Pakhra
Synchrotron. Phys.Part.Nucl. 52 (2021) 4, 663.
[5] M. Bhattacharjee et al. Calibration of NICA-MPD electromagnetic calorimeter modules with
cosmic muons. 2020 J. Phys.: Conf. Ser. 1690 012052.

SPD (Spin Physics Detector) collaboration proposes to install a universal setup in the second interaction point of the NICA collider (JINR, Dubna) to study the spin structure of the proton and deuteron. It will be able to research of spin-related phenomena with polarized proton and deuteron beams at a collision energy up to 27 GeV and a luminosity up to 10$^{32}$ cm$^{-2}$ s$^{-1}$. In this report we inform about the basic tasks of SPD project. We manufactured a test bench MiniSPD to check the SPD detector prototypes with cosmic muons. The current results of simulation and comparison with data on cosmic rays at this stand are presented.

The LHCb Upgrade phase II aims to collect $300 fb^{-1}$ in a few years operating at a luminosity of $1.5*10^{34} cm^{-2} s^{-1}$. This requires a significant change of the systems including the electromagnetic calorimeter (ECAL), which must be capable to sustain integrated radiation doses up to 1 MGy in the innermost region. The second major requirement is time resolution of the order of a few tens of picoseconds. The new ECAL will be subdivided into zones: spaghetti calorimeter (SPACAL) in the central part with the highest expected radiation doses and zones with Shashlik-type modules of different granularity.
The SPACAL region is subdivided into an innermost region with tungsten 3D-printed absorber and radiation hard crystals (e.g. GAGG, GFAG) with $15*15mm^2$ cell size, and an intermediate region with a cast lead-based absorber and polystyrene scintillating fibres.
This talk presents the results of the first cast lead-polystyrene spacal prototype studies performed with an electron beam at the CERN SPS test-beam facility.

The NA61/SHINE is a fixed target experiment at SPS (CERN) aimed to study proton-ion and ion-ion collisions with the energy range 13 – 150 AGeV. A new physics program of the NA61/SHINE experiment beyond 2020 includes open charm measurements. The increased by an order of magnitude beam rate requires detectors upgrade to work with high trigger rate and to survive in new high radiation conditions.

The Projectile Spectator Detector (PSD), a sampling hadron calorimeter, is used in the NA61/SHINE experiment to measure the collision centrality and reconstruct the event plane. Instead of the present PSD, two forward calorimeters are used. The first one is modified current PSD with beam hole in the center and the second one is a new calorimeter with small transverse sizes placed downstream to detect heavy fragments. Details of the PSD upgrade as well as results of the performance studies for new calorimeter system with simulations will be presented.

Detection of low energy neutrino is a challenging task for advanced
studies of coherent neutrino scattering processes or for the observation
of neutrino magnetic momentum. For this purpose, the detector must be
capable to register the deposited energies starting from a hundred of
eV. One of the option is the development of CsI(pure) scintillation
detector operating at the temperature of liquid nitrogen. It is known,
that this scintillator could achieve the record light yield of about 120
thousand photons per one MeV of deposited energy. It means that 100 eV
energy deposition corresponds to 12 photons, that can be detected by
advanced photodetectors.In this work we present the performance of
small CsI(pure) scintillation cell which is readout by compact silicon
photomultiplers (SiPM) with high detection efficiency. The SiPM thermal
noises and the achieved light collection efficiency are presented. It
will be shown that signal of about 30 photoelectrons/keV is attainable
in such configuration of detector.

Studying spin-related phenomena will help uncover information about internal structure of nucleon. It can be done using polarized beams of protons and deuterons. To study those effects on NICA collider it is proposed to install the Spin Physics Detector(SPD) in one of two interaction points.

In this work two problems were studied. First is developing a fast and accurate algorithm for determination of $pp$-collision time($t_{0}$) for the SPD experiment [1]. Second is developing particle a identification(PID) procedure based on $TOF$ signals.

Usage of $TOF$ detectors to identify particles is one of the most reliable technique. To reconstruct the particle mass only three values are needed: $\vec{p}$ - momentum of the particle, $L$ - arc length of the particle trajectory and $TOF$ - Time-Of-Flight. To measure $TOF$ one needs start($t_{0}$) and stop signals. While stop signals are obtained with $TOF$ detector, $t_{0}$ cannot be measured directly. Main idea for $t_{0}$ determination: for tracks in the event find a set of masses that minimises sum of the squares of the residuals ($\chi^{2}$).

To solve $\chi^{2}$ minimisation problem Differential Evolution-inspired [2] Genetic Algorithm(GA) was developed and it's results were compared to Brute Force Algorithm(BFA). BFA have very slow run time, but it provides the exact solution to the $\chi^{2}$ minimisation problem. So main requirements to GA was to decrease run time while keeping high accuracy.

With a reliable method for $t_{0}$ determination, particle identification can be performed. There are several approaches that can be used for PID procedure [3]. In this work Bayesian approach, "n-sigma" criteria and solution for $\chi^{2}$ minimisation problem were compared.

1. Conceptual design of the Spin Physics Detector. arXiv:2102.00442
2. E. Zhabitskaya and M. Zhabitsky,
   Proceedings of the 15th annual conference on Genetic and evolutionary computation, GECCO'13, ACM, 455--462 (2013)
3. The ALICE Collaboration., Adam, J., Adamová, D. et al. Particle identification in ALICE: a Bayesian approach. Eur. Phys. J. Plus 131, 168 (2016). https://doi.org/10.1140/epjp/i2016-16168-5

The results of development and laboratory testing of a prototype data concentrator integrated circuit (ASIC HUBv1) are presented. HUBv1 was developed for processing of signals from the detector chips of the time-projection chamber of the MPD experiment (NICA, Dubna). The main target of this ASIC is uninterrupted processing and serialization of digital output data from two SAMPA detector chips and their transmission via AWG-36 type cables up to 1 m long at the speed of 2.56 Gbit/s to the data acquisition controller board. Eight data and six SLVS clock ports are used to connect the SAMPA chips. The received data is error-checked using Hamming code and is available on the two high-speed CML output ports, each with bandwidth up to 2.56 Gbps. Both SAMPA and SIMC chips are controlled by issuing control commands via the high-speed CML or slow SPI interfaces.
The HUBv1 prototype was manufactured using TSMC's 65 nm CMOS technology and packaged in CPGA120-type packages. The total power consumption of the ASIC does not exceed 500 mW. The results of laboratory testing of the chip and radiation resistance testing of the analog blocks are presented.

The development of key building blocks of a prototype application specific integrated circuit (ASIC) for the SPD experiment at NICA Nuclotron (Dubna) is presented. It was designed as an 8-channel fully differential amplifier-discriminator which could be used as a front-end electronics for resistive plate chambers as well as for time-of-flight measurements.

The ASIC has an architecture similar to the NINO chip developed at CERN. Each channel consists of the following functional blocks: a current preamplifier-shaper with the peaking time of 500 ps, low-frequency feedback with built-in threshold preset circuit, few additional amplification stages, pulse stretcher, LVDS output stage and some other supporting blocks. The chip is optimized for the input capacitance in range 1-10 pF, has adjustable threshold of 10-450 fC, and adjustable stretching time of 1-100 ns. The equivalent noise charge is not more than 2500 e at input capacitance up to 10 pF. The design was optimized for reducing front-edge jitter (less than 15 ps). Both schematic and layout of designed blocks are presented, simulation results are shown. PVT variation and Monte-Carlo mismatch plots are also given.

The development was conducted in the 180 nm CMOS process PDK of Mikron fab at Zelenograd. GDSII file was submitted to the factory at late August 2022.

A.T. D’yachenko$^{1,2}$

$^{1}$ National Research Center “Kurchatov Institute” B.P. Konstantinov Petersburg Nuclear Physics Institute, Gatchina, Russia;
$^{2}$ Emperor Alexander I Petersburg State Transport University, St. Petersburg, Russia

We managed to completely describe the spectra of cumulative protons, pions and photons for the collision of carbon nuclei with a beryllium target in the energy range of 0.3-3.2 GeV per nucleon obtained in the ITEP experiments [1,2,3]. To do this, it was proposed to solve the kinetic equation together with the solution of the equations of hydrodynamics [4, 5]. When describing these spectra, the correction for the microcanonical distribution [4, 5] was taken into account, and the contribution of the fragmentation process was also taken into account for the proton yields. It is shown that our description of the experimental data is better than the cascade models and the quantum molecular dynamics (QMD) model built into the GEANT4 package and the HSD (hadron string dynamics) model [6].
Our approach is applicable to collisions of both light and heavy nuclei, which can be seen from a comparison of the description of the proton distributions in transverse momentum in the Au+Au reaction at an energy of 1.48 GeV per nucleon with experimental data and other theoretical approaches based on solving the Boltzmann equation, the model of quantuml molecular dynamics, etc. [7]. This can be extended to the energy range of the accelerator complex NICA located at the JINR (Dubna) in order to study the quark-gluon plasma
The contribution of the effects of short-range correlations (SRC), which has recently received much attention [8], was also studied by us. As a result, it turned out that these effects are included in our approach, since we successfully describe the experimental data on the spectra of hard photons [9], which are described in [8] with the addition of a high-momentum component.

1.B.M. Abramov et al., Phys. Atom. Nucl. 78, 373 (2015).

2.I.G. Alekseev et al., Phys. Atom. Nucl. 78, 936 (2015)

3 B.M. Abramov et al, Phys. Atom. Nucl. 84, 467 (2021).

4.A. T. D'yachenko, I. A. Mitropolsky, Phys. Atom.Nucl. 83, 558 (2020).

5.A. T. D’yachenko, I. A. Mitropolsky, EPJ Web Conf. 204, 03018 (2019)

6 W. Cassing, E. Bratkovskaya, Phys. Rept. 308, 65 (1999).

7.E. E. Kolomeitsev et al. J Phys. G 31 741(2005)

8.W.M. Guo, B.A. Li, G.C. Yong, Phys. Rev. C 104.034603 (2021)

9.J. Stevenson et al., Phys. Rev. Lett. 57, 555 (1986).

Bose–Einstein correlations of charged pions in Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV from UrQMD

A. Kraeva${}^{1,2}$, G. Nigmatkulov${}^{1,2}$

E-mail: annakraeva555@gmail.com, nigmatkulov@gmail.com

The method of correlation femtoscopy makes it possible to estimate the parameters of the particle-emitting region (radius of emission region, $R$, and correlation strength, $\lambda$). Measurement of femtoscopic radius dependence on transverse momentum of particle pairs, $k_T$, is an important tool for studying the dynamics of the emission process [1].

This work is devoted to the study of momentum correlations of identical pions produced in Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV using the UrQMD (Ultrarelativistic Quantum Molecular Dynamics) model [2, 3]. Three-dimensional femtoscopic analysis was performed as a function of $k_T$, rapidity and collision centrality. Physical implications will be discussed.

References:

[1] Lisa M.A. et al. Femtoscopy in relativistic heavy ion collisions: two decades
of progress // Annu. Rev. Nucl. Part. Sci. – 2005. – V.55. – P.357.

[2] Bass S.A. et al. Microscopic Models for Ultrarelativistic Heavy Ion Collisions // Prog. Part. Nucl. Phys. – 1998. – V.41. – P.225.

[3] Bleicher M. et al. Relativistic Hadron-Hadron Collisions in the Ultra-Relativistic Quantum Molecular Dynamics Model // J. Phys. G: Nucl. Part. Phys. – 1999. – V.25. – P.1859.

${}^1$National Research Nuclear University MEPhI, Moscow, 115409, Russia

${}^2$Joint Institute for Nuclear Research (JINR), Dubna, 141980, Russia

Collisions of oxygen nuclei are planned in future LHC runs to scan the size of colliding systems at ultrarelativistic energies [1]. As shown by calculations [2,3], the admixture of the alpha-clustered states in O-16 leads to a triangular modulation of elliptic flow from the overlap region of colliding nuclei. The measurements [4] and modelling [5,6] of fragmentation of O-16 projectiles of lower energies of few GeV/nucleon demonstrated the enhanced production of spectator alpha-particles resulting from the alpha-clusterization in O-16.

In the present work a new version of the Abrasion-Ablation Monte Carlo for Colliders model (AAMCC-MST) is used to simulate O-16–O-16 collisions at the LHC. The model takes into account pre-equilibrium clusterization of spectator matter [7,8] and the admixture of alpha-clustered states in O-16 (AAMCC-MST) [5]. Three nuclear density profiles in O-16 were implemented in AAMCC-MST to sample the positions of neutrons and protons in O-16 [5]. The cross sections to produce various spectator nuclei (He, Li, Be, B, C, N) at the LHC and the multiplicity distributions of spectator alpha-particles are calculated and compared to the results obtained at lower collision energies. The production of spectator deuterons is also investigated as a possible indicator of the short-range correlations in nuclei [9]. The obtained results can help in evaluating the performance of Zero Degree Calorimeters in future LHC experiments on O-16–O-16 collisions.

References

[1] Z. Citron et al., CERN Yellow Rep. Monogr. 7 (2019) 1159

[2] W. Broniowsky et al., Nucl. Phys. A 1005 (2021) 121763

[3] S.H. Lim et al., Phys. Rev. C 99 (2019) 044904

[4] M. El-Nagdy et al., J. Phys. Commun. 2 (2018) 035010

[5] A.Svetlichnyi et al., Phys. Atom. Nucl., 2022, to be published

[6] A. Svetlichnyi et al., PoS, EPS-HEP2021 (2022) 310

[7] R. Nepeivoda, et al., Particles 5 (2022) 40

[8] N.Kozyrev et al. Eur. Phys. J. A 58 (2022) 184

[9] M.Alvioli et al., Phys. Lett. B 680 (2009) 225

Experimental results of ALICE collaboration on the emission of forward neutrons in ultraperipheral collisions of $^{208}$Pb nuclei at $\sqrt{s_{\mathrm{NN}}}=2.76$ and $5.02$ TeV are reviewed. Electromagnetic dissociation (EMD) events with the lowest multiplicity of 1, 2 or 3 neutrons dominate at both collision energies. The cross sections for 1n – 5n emission with and without protons were measured by means of forward zero degree calorimeters (ZDCs). The obtained cross sections for neutron emission accompanied by an arbitrary number of protons can be used to validate various EMD models. According to the Relativistic ELectromagnetic DISsociation model (RELDIS), the cross sections of protonless neutron emission, measured for the first time by ALICE at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, can be considered as upper limits for the cross sections of the production of the respective secondary nuclei, $^{207,206,205,204,203}$Pb, in EMD of $^{208}$Pb.

The HYDJET++ event generator is a phenomenological model of heavy-ion collisions that treats the collision process as a combination of a soft hydro-type state and a hard state resulting from hard parton scattering.
On the one hand, it allows one to quickly simulate relativistic heavy-ion
collisions, and on the other hand, it reproduces and describes a number
of experimental phenomena in the soft and hard sector. It also allows
you to study many features of the interaction as interplay of soft and
hard processes.
Here we present some selected results of recent studies. Basically,
new results on the correlation of elliptical flows at small and large
transverse momenta at LHC energies are described. Some current
studies of the charge balance function at LHC energies and the
A-dependence of the flow in heavy-ion collisions are also discussed.

The data [1] on spectra of $K_S^0$ mesons measured by the STAR Collaboration in $\rm Au+Au$ collisions at various centralities characterized by different multiplicity densities of negative particles were analyzed in the $z$-scaling approach [2,3]. The transverse momentum distributions obtained in the BES-I program at RHIC were accumulated in seven centrality classes from the most central $(0-5)\%$ to peripheral $(60-80)\% $collisions in the rapidity range $|y| < 0.5$. These data and the earlier STAR data at $\sqrt s_{NN} = 62, 130$ and $200$ GeV allow us a detail study of the energy and centrality dependence of $K_S^0$-meson production in a wide range of $\sqrt s_{NN} = 7.7–200$ GeV. The entropy of the microscopic configurations accompanied of $K_S^0$-meson production in $\rm Au+Au$ collisions, is constructed. It is expressed, in the $z$-scaling approach, via the momentum fractions of colliding particles and scattered constituents fragmented to produced particles, the structural and fragmentation fractal dimensions, the multiplicity density of negative particles and model parameter $c_{AuAu}$ interpreted as a specific heat of produced medium. The irregularity in the behavior of the specific heat parameter $c_{AuAu}$ was connected in [4] with existence of a phase transition in nuclear matter. The dependence of the entropy $\rm S$ on the collision energy $\sqrt s_{NN}$ over the range $7.7-200$ GeV for most central $(0-5)\%$ and peripheral $(60-80)\%$ events was studied as a function of transverse momentum of produced of $K_S^0$-meson. It was found that the values of the entropy in peripheral collisions at low $\sqrt s_{NN}$ are much smaller than in the central ones. Non-trivial dependence of $\rm S$ on the collision energy with decreasing $p_T$ was found. The entropy reaches a local maximum at the energy
$\sqrt s_{NN} = 11.5 - 19.6$ GeV for $p_T = 0.3$ GeV/c. This is followed by an abrupt fall of $\rm S$ at $\sqrt s_{NN} = 27 - 39$ GeV with a gradual increase at higher energies. Such anomalous behavior is also visible at $p_T = 0.6$ and $1.0$ GeV/c in the same energy range. At higher $p_T \ge $2 GeV/c, the entropy $\rm S$ becomes a monotonously increasing function of the collision energy and the observed anomaly of $\rm S$ disappears. The monotonic growth of $\rm S$ is seen for all $p_T$ in the peripheral collisions.

1. J. Adam et al. (STAR Collaboration), Phys. Rev. C102,034909 (2020).
2. M. Tokarev et al., Phys. Part. Nucl. 51, 141 (2020).
3. M. Tokarev, A. Kechechyan, I. Zborovský, Nucl. Phys. A993, 121646 (2020).
4. M. Tokarev, I. Zborovský, Nucl.Phys. A1025, 122492 (2022).

The helicity of quark-gluon medium is transmitted to spin polarization through axial anomaly. The possibilities of distinguishing of this mechanism, incorporating the recent data, from the thermodynamic one are discussed. The other manifestations of helicity, mimicking the chiral magnetic and vortical effects are also considered.

In high energy physics, software infrastructure for the analysis of experimental data is tightly connected with the specifics of experiment: detector setup, collision system, reconstructed event and track information. However, the aspects of physics analysis are common. In this work, we present a framework for correlation femtoscopy technique that could be applicable for any experiment.

It is developed in an object-oriented paradigm using a combination of software design patterns [1]. As a result, the polymorphic behavior of the framework encapsulates the data differences, providing a universal way to manage the analysis of any experiment. The additional interface, based on C++ typecasting features, allows users to control parameters that are unique for the experiments. C++ language and CERN ROOT libraries are used for implementation.

References:
[1] E. Gamma et al. Design Patterns: Elements of Reusable Object-Oriented Software. Reading, Mass.: Addison-Wesley, 1995.

The correlation between particles produced at various pesudorapidity values is an important probe to disentangle the underlying dynamics of multi-particle production in high energy collisions.
The long-range correlations are believed to be free from final-state effects.
The correlation strength ($b_{corr}$) has been studied for forward ($N_{F}$) and backward ($N_{B}$) charged partice multiplicities.
The $b_{corr}$ has been investigated as a function of gap between the forward and backward pesudorapidity windows as well as the width of these windows.
These $b_{corr}$ has also been studied for positively and negatively charged particle multiplicity in forward and backward intervals, respectively.
The strongly intensive fluctuation measure ($\Sigma$), which reduces to unity in absence of any inter-particle correlations, has also been investigated by employing the two extensive variables i.e., $N_{F}$ and $N_{B}$.

The effect of processes like multiparton interaction (MPI) and color reconnection (CR) is also taken into account.
The events have been simulated for proton-proton and Pb-Pb collisions at the Large Hadron Collider energies using the Pythia8 event generator.

[1] Adam, Jaroslav, et al. Journal of High Energy Physics 2015.5 (2015): 1-28.

[2] Gorenstein, M. I., and M. Gaździcki, Physical Review C 84.1 (2011): 014904.

[3] Gazdzicki, Marek, M. I. Gorenstein, and M. Mackowiak-Pawlowska, Physical Review C 88.2 (2013): 024907.

[4] Sjöstrand, Torbjörn, et al. Computer physics communications 191 (2015): 159-177.

The possible appearance of the effects of local parity breaking in the QCD medium formed in heavy ion collisions can happen due to violation of chiral symmetry, the difference between the average densities of right- and left-handed quarks in the fireball [1]. In the statistical approach, it can be quantified by corresponding chiral chemical potential $\mu_5$ [1,2]. The experimental observables sensitive to the effects of local parity violation in strong interaction include search for polarisation splitting of the $\rho^0$ and $\omega^0$ mesons via angular dependence of spectral functions in their decay to leptons [3,4]. In this report we estimate the space-time evolution and fluctuations of $\mu_5$ using relativistic hydrodynamics [5] and their effect on the light meson polarization splitting in Pb-Pb collisions at LHC energy.

The study was funded by the Russian Science Foundation grant No. 22-22-00493, https://rscf.ru/en/project/22-22-00493/

1. A. A. Andrianov, V. A. Andrianov, D. Espriu, and X. Planells, Phys. Lett. B, 710, 230–235 (2012).
2. V. V. Braguta et al., Phys. Rev. D 93, 034509 (2016)
3. A.A.Andrianov, V.A.Andrianov, D.Espriu and X.Planells, Phys. Rev. D 90, no.3, 034024 (2014)
4. Vladimir Kovalenko, Alexander Andrianov, and Vladimir Andrianov. J. Phys. Conf. Ser., 1690(1): 012097, 2020.
5. Bjoern Schenke, Sangyong Jeon, and Charles Gale, Phys. Rev. C 82, 014903 (2010).

Using the fact that neutrinos only participate in weak and gravitational interactions, we explore the possibility of having their masses emerged at the intersection between extended electroweak theory and theory of gravity. We describe how these two seemingly incompatible theories could be embedded in a lepton-number violating 5-dimensional Lagrangian L5. A peculiar feature of this approach is its ability to generate effective Majorana neutrino masses via the spontaneous symmetry breaking (SSB) of Grand Unified Theory (GUT), $GGUTMX−\rightarrow−G(321)\upsilon EW−\rightarrow−G(1)$ and $4\times4$ symmetric matrix of gravitational couplings. Within the purview of this theoretical framework, we obtain values for the effective Majorana mass Mmasseff=3.7126 meV, and the Majorana neutrino masses $m_1=0.6672$ meV, $m_2=14.4498$ meV, $m_3=43.3494$ meV, $m_4=0$ meV and $\Sigma m=0.0585$ eV. Our results are in good agreement with both experimental and cosmological data.

A non-minimal expansion of the Majorana fermions mass matrix in the framework of the type I see-saw mechanism is considered. The original parametrizations of mixing and mass matrices of the light and the heavy neutrinos are obtained. It is shown that (i) the effective mass matrix is independent on an approximation, (ii) new contributions in the expansion are of the same order as those used in describing bariogenesis in the early Universe. The model regimes in which higher order corrections may be important are discussed.

The interaction of neutrinos with photons at high energies is considered within the standard electroweak theory. It is pointed out that the theory admits the presence of resonant channels in the production of massive bosons in neutrino$-$photon reactions. Some consequences of the existence of such channels for scattering of neutrinos on atomic nuclei are discussed. In particular, we show the possibility of excitations of the CP-conjugate of the Glashow resonance in large-volume neutrino detectors, as the IceCube, Baikal-GVD and KM3NeT.

Spin Physics Detector (SPD) will be created at NICA accelerator facility in Dubna, Russia. One of the aims of the experiment is a study of spin effects in polarized proton-proton and deuteron-deuteron collisions at high energies. The other very important aim is an extraction of gluon distribution function of nucleons. Minimal bias interactions will be studied also. We will consider problems of soft hadronic collisions what can be investigated, namely, average Pt correlations with Feynman-x variable (xF) of produced particles, and 2-particle Pt correlations. The LEBC-EHS collaboration presented in 1991 Pt-xF correlations in pp-interactions for Pi+-, K+- mesons, anti-protons and protons at Plab=400 GeV/c. The correlations grow up very fast at xF-> 1. Monte Carlo model – FRITIOF existing at that time, could not be able to quantitively describe the data. A modern FRITIOF model implemented in the Geant4 package (FTF model) also has some problems. We will present FTF results in a comparison with PYTHIA model ones. In order to understand a nature of the correlations, we propose to study 2-particle Pt correlations at future SPD experiment. Essence of the last correlations will be also considered.

As known, the NICA accelerator facility is creating in Dubna, Russia. Two experiments are planned at NICA - Spin Physics Detector (SPD) and Multi Purposes Detector (MPD). The aim of the SPD experiment is a study of spin effects in polarized proton-proton and deuteron-deuteron collisions at high energies, and an extraction of gluon distribution function of nucleons. The MPD experiment is going to study in details the transition from ordinary matter to the quark-gluon plasma (QGP). It is assumed that the transition can take place at NN center of mass energy about 10 GeV. Studies of collective flow effects, particle composition and so on are foreseen at MPD. But modern experiments performed within the Beam Energy Scan (BES) program of RHIC al low energies do not show bright results. Thus, additional possibilities of experimental studies have to be considered. Recently, we have analyzed experimental data by the NA61/SHINE collaboration on Ar+Sc interactions at 13, 19, 31, 75 and 150 GeV/c on projectile nucleon in the target rest frame within the framework of Geant4 FTF (Fritiof) model. The model does not assume a creation of QGP. The model well describes negative charged pion spectra in Ar+Sc collisions with 0 – 5 % centralities at momenta 13, 19, 31 and 40 GeV/c. At higher momenta, the model underestimates the data leaving a room for QGP. Thus, we conclude that QGP can be appeared at energies larger than 9 GeV. General features of Be-7 + Be-9 interactions studied also by the collaboration are described well by the FTF model at all pointed energies. Though, there is a problem with a reproduction of K+ meson spectra. The problem and FTF model results will be presented in our report.

Experimentally, correlations between multiplicity of charge particles and the mean transverse momentum were seen in $p+p$ collisions from the highest SPS energy to the LHC energy. The extension of the experimentally established pattern of the change from negative correlations at energies $\sqrt{s}$ = 17–40 GeV by measurements at lower energies is particularly significant [1]. This set of results can make a significant contribution to the development of theoretical models and approaches. It was shown that the average transverse momentum is sensitive to changes in bulk viscosity, so experimental data on the study of correlations between mean transverse momentum and multiplicity of charge particles may impose significant restrictions on the relativistic hydrodynamic model [2]. Previously, in the SMASH and EPOS models, a non-trivial dependence of strongly intensive variables on the collision energy was shown, namely, for the $\Delta[p_{t}, N]$ [3] and $\langle N \rangle D[p_{t}, N]$ [4] (two-particle pt correlation). It was also shown that the second and third moments of the transverse momentum deviate from the picture of independent sources, which is confirmed by experimental data obtained from the collision of $Au+Au$ at an energy of 200 MeV [5]. Between the EPOS and SMASH models, a discrepancy was found in the third order cumulant pt (skewness) dependency on collision energy. In this investigation, for a more complete study of correlations, we will analyze the dependence of strongly intensive quantities and second and third moments on energy using PHSD[6] and UrQMD[7] models which combines the string model and resonances.

Acknowledgements. This research has been conducted with financial support from St. Petersburg State University (project No 93025435).

[1] N. Armesto et al., Phys. of Atom. Nucl., 71. 2087-2095 (2008)

[2] S. Ryu et al., Phys. Rev. Lett., 115, 132301. (2015)

[3] M. Gorenstein, M. Gazdzicki, Phys. Rev. C 84, 014904 (2011)

[4] M. Cody et al., arXiv:2110.04884 [nucl-th] (2022)

[5] X.-N. Wang, M. Gyulassy, Phys. Rev. D. 44. 3501-3516 (1992)

[6] E. Bratkovskaya et al., arXiv:1908.00451 [nucl-th] (2019)

[7] M. Bleicher et al., arXiv:hep-ph/9909407 [hep-ph] (1999).

Phenomenological model of color quark-gluon strings as particle emitting sources [1] is developed and used to study correlations in rapidity of different event observables such as multiplicity and mean particle transverse momenta [2]. The color strings dynamics at initial stages of the relativistic collisions is considered both in rapidity dimension [3] and in transverse plane [4]. The former is defined by the partons momenta at string ends, while the latter is represented by strings interaction via sigma meson exchange. Providing this 3-d density, strings can partially overlap, which leads to their fusion and modifications of production characteristics [5]. Model results are compared with the PYTHIA event generator and available data on p+p inelastic interactions.

Acknowledgements. This research has been conducted with financial support from St. Petersburg State University (project No 93025435).

1. D. S. Prokhorova and V. N. Kovalenko, Phys. Part. Nucl. 51, 323 (2020)
2. V. Vechernin, Nuclear Physics A 939, 21 (2015)
3. C. Shen and B. Schenke, Phys. Rev. C 105, 064905 (2022)
4. T. Kalaydzhyan, E. Shuryak, Phys. Rev. C 90(1), 014901 (2014)
5. M.A. Braun, C. Pajares, Phys. Lett. B 287, 154 (1992)

Multiple particle production in pp interactions at LHC energies is considered in a model with quark-gluon strings (color flux tubes) as sources, assuming the string cluster formation. Within this model multiplicity distributions of charged particles, their combinants and the properties of the strongly intense variable Σ, which characterizes the correlations between the number of particles in two observation windows separated in rapidity, are studied. We use a Regge-like quasi-eikonal approach to find the distribution of strings in the transverse plane of pp-collision. This allows us to take into account string fusion processes leading to the formation of string clusters using a finite lattice (grid) in the impact parameter plane. Analytical calculations supplemented by MC simulation, make it possible to find the multiplicity distributions and corresponding combinants as well as the dependences of the variable Σ both on the width of the observation windows and on the size of the gap between them for different initial energy and centrality of pp collisions.

We show that in pp collisions at LHC energies, string fusion effects leading to the formation of string clusters have a significant effect on the behavior of considered observables. We see that the so-called modified combinants found from the calculated multiplicity distributions are indeed very sensitive to the shape of the multiplicity distribution spectra, and that our string clustering model reproduces the general experimental behavior of the combinants obtained from ALICE and CMS data, in particular, their oscillations.

We also demonstrate that the experimentally observed dependence of the strongly intensive variable Σ on the initial energy and centrality of pp collisions can be explained only in the presence of sources of different types, the role of which in our model is played by single strings and clusters formed by the fusion of several strings. It is also shown that a comparison of the results of our model with the preliminary experimental data of ALICE makes it possible to extract the parameters of clusters with different numbers of merged strings, in particular, to find their two-particle correlation functions.

The research was supported by the SPbSU project, No 93025435.

O.M. Shaposhnikova1, A.A.Marova 2, G.A. Feofilov2,*

1 St. Petersburg Governor's Physics and Mathematics Lyceum No. 30

2 Federal State Budgetary Educational Institution of Higher Education "Saint-Petersburg State University", Saint Petersburg, 199034 Russia

*E-mail: g.feofilov@spbu.ru

Abstract:

We consider a correction to the Bjorken energy density[1] calculations [2-6 ] where the information is usually taken from the nucleus-nucleus collisions events selected in a certain centrality class. The last one is usually defined in terms of some observarble (multiplicity of particles, number of participating nucleons, transverse energy) used as a proxy to the impact paramemer b. However, due to the natural dominance of peripheral collisions in any class of
centrality, the relevant mean values of the impact paramemer will be always shifted towards some higher values. For example, it is possible to show that in case of 0-5% centrality class of A-A collisions, the value is considerably shifted from 0 ( ~ 2 fm), therefore in this case the corresponding value of ST - the transverse interaction area of two overlapping
colliding disks, should not be taken to be that of a circle. It appears to be smaller, thus resulting in the higher values of energy density finally calculated for a given class.

The calculation based on next-to-leading logarithm (NLL) approximation for Balitsky-Fadin-Kuraev-Lipatov (BKFL) evolution is discussed for Mueller-Navelet (MN) dijet production cross section as well as ratios of cross sections with veto as functions of rapidity separation $\Delta y$ between jets in dijet. The NLL BFKL calculations employ optimal renormalization scale procedure generalized for non-abelian theories by Brodsky-Fadin-Kim-Lipatov-Pivovarov. The veto on additional jet activity above $p_{T\mathrm{veto}}$ is accounted with Banfi-Marchesini-Smye approach. The results are compared to the CMS measurements in proton-proton collisions at $\sqrt{s}$ = 7 and 2.76~TeV.

NICA is a new flagship project at JINR aimed at the construction in Dubna of an accelerator complex for heavy ions and polarized particles. The main goal of the MPD experiment at NICA is the exploration of the structure of the phase diagram of dense nuclear matter. Hypernuclei are used as a laboratory offering the opportunity to study the properties of strong interactions involving hyperons, which play a key role in understanding of the structure of neutron stars. Аccording to thermal model calculations, a pronounced maximum of the production rates of hypernuclei is expected at NICA energies. This will potentially allow determination of the hypernuclei properties, including lifetimes, with high precision improving the quality of the existing results.
In this report, an overview of recent hypernuclei measurements will be given and MPD prospects for the study of hypernuclei production in heavy-ion collisions at NICA energies will be presented.

We present results of simulations of the light-nuclei production in relativistic heavy-ion collisions within the updated event generator based on the three-fluid dynamics (3FD), complemented by Ultra-relativistic Quantum Molecular Dynamics (UrQMD) for the late stage of the nuclear collision~--- the Three-fluid Hydrodynamics-based Event Simulator Extended
by UrQMD final State interactions (THESEUS).
The light-nuclei production is treated with the thermodynamical approach on the equal basis with hadrons.
The simulations were performed for Pb+Pb and Au+Au collisions in the collision energy range of $\sqrt{s_{NN}}=$ 6.4--19.6 GeV. Their results are compared with available data from the NA49 and STAR collaborations, rapidity distributions and transverse-momentum spectra.
The updated generator revealed not perfect, but a reasonable reproduction of the data on the light nuclei, especially the functional dependence on the collision energy and light-nucleus mass.
It is important that this reproduction is achieved without any extra parameters, while the coalescence approach in 3FD requires special tuning of the coalescence coefficients for each light nucleus separately.
The collective flow, directed and elliptic ones, are also considered.

The study of the hadron matter properties under extreme conditions of high baryon density, energy and strong electromagnetic fields in heavy ion collisions is one of the most important problems in modern high-energy physics. The striking example of such state of matter is the quark-gluon plasma (QGP). One of the possible ways to study the properties of quark-gluon plasma is the so-called electromagnetic probes - photons and leptons. Since these particles freely leave the plasma volume practically without interacting with hadron matter, they can carry direct information about the processes in the QGP.

The report is devoted to the specific mechanism of photon production by conversion from two gluons gg → γ in the framework of the mean-field approach to the QCD vacuum. According to the domain model of QCD vacuum, the confinement phase is dominated by Abelian (anti-)self-dual gluon fields, while the deconfinement phase is characterized by a strong chromomagnetic field. In the confinement phase, the production probability of two gluons into a photon vanishes due to the random orientation of the statistical ensemble of confining vacuum fields. In contrast, strong magnetic field with singled direction is generated by relativistic heavy ion collisions and plays the role of a trigger for the deconfinement phase transition. This transition is accompanied by chromomagnetic field with the same direction as the magnetic field. As a consequence, the conditions of Furry theorem are violated, and the conversion probability of two gluons into photon is nonzero, and their distribution has a strong angular anisotropy. Thus, the photon production in the investigated process can act as one of the important signals of transition of hadronic matter to the deconfinement phase.

The model analysis of particle production in heavy ion collisions depending on number of emission sources (wounded nucleons or partons) at different centralities is performed in a wide collision energy range from RHIC to LHC and for all measured pair of heavy ions.

The model of wounded partons based on Glauber calculations gives better scaling for the ratio of charged particle multiplicity to the number of wounded constituent partons $N_{ch}/N_{c-part}$ depending on collision centrality for all considered energies and colliding systems.

Also, the eccentricity density distribution in Glauber Monte Carlo framework has been fulfilled for several centrality intervals. Assuming linear dependence between eccentricity and elliptic flow, the eccentricity density distribution is compared with CMS data on flow fluctuations for Pb+Pb collisions at $\sqrt s_{NN} = 5.02$ TeV data. The probability density distribution with wounded partons better describes experimental data for more central collisions.

The NA61/SHINE experiment at the CERN SPS has recently extended its program for the energy scan with Pb ions. In the past, the NA49 experiment, which preceded NA61/SHINE, also recorded data for Pb-Pb collisions at different energies. Together, the two experiments
cover a wide range of beam energies provided by the CERN SPS in the range 13 - 150 A GeV/c. Analysis of the new NA61/SHINE data and reanalysis of the existing NA49 data
using modern measurement techniques allow for a new comprehensive systematic study of collective flow relative to the spectator plane.
We will present new NA61/SHINE results on directed and elliptic flow measurement in Pb-Pb collisions at 13 and 30A GeV/c relative to the spectator plane determined with the Projectile Spectator Detector. Also a new analysis of 40A GeV data collected by the NA49 experiment using forward spectator calorimeters (VETO and RCAL) will be shown. The flow coefficients are reported as a function of rapidity and transverse momentum in different classes of collision centrality. The new results are compared with existing results from the previous NA49 analysis and the STAR experiment at RHIC.

The results on the the vector Ay and tensor Ayy and Axx analyzing powers in deuteron-proton elastic scattering at large scattering angles are presented. These data were obtained at internal target at JINR Nuclotron in the energy range 400-1800 MeV using polarized deuteron beam from new polarized ion source. New data on the deuteron analyzing powers in the wide energy range demonstrate the sensitivity to the short-range spin structure of the isoscalar nucleon-nucleon correlations.

Two particles angular correlations are a useful tool to study the mechanisms of particle production by observing the angular correlation (∆η,∆ϕ) between pairs of particles in an event. Different structures in the ∆η − ∆ϕ space are caused by various mechanisms of particle production and interactions between particles shortly after production. Examining these structures can give us insight
into the nature of nuclear interactions.

The clusters have been observed experimentally at midrapidity from SIS up to LHC energies. However, the understanding of the mechanisms for the production of weakly bound clusters in heavy-ion reactions is still one of the challenging puzzles nowadays, usually called "ice in a fire".
In the Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) clusters are formed dynamically due to the interactions between baryons described on the basis of Quantum Molecular Dynamics which allows to propagate the n-body Wigner density and n-body correlations in phase-space, which is essential for the cluster formation.
We report on new results and recent developments of the PHQMD transport approach.

Centrality is an important concept in the study of strongly interacting matter created in a heavy-ion collision whose evolution depends on its initial geometry. Experimentally collisions can be characterized by the measured multiplicities or energy of produced particles or spectator fragments. Relation between collision geometry and experimentally measured multiplicities is commonly evaluated within the Monte-Carlo Glauber approach.

We will present methods for centrality determination in heavy-ion collisions with the Baryonic Matter at Nuclotron (BM@N) experiment. The multiplicity of charged hadrons is provided by the BM@N Silicon Tracking System (STS) and Gaseous Electron Multiplier (GEM) detectors and connected to collision geometry parameters using the Monte-Carlo Glauber model. The energy of projectile spectator fragments is estimated with the BM@N Forward Hadron Calorimeter (FHCal) and Hodoscope detectors. We will also touch possibilities to determine centrality using the spectators’ fragments and Monte-Carlo Glauber model.

Selection of the very recent results by the Compact Muon Solenoid (CMS) Collaboration on heavy-ion physics in relativistic collisions at LHC energies will be presented.

The cool storage ring (CSR) external-target experiment (CEE) will be the first large-scale nuclear physics experiment at the Heavy Ion Research Facility in Lanzhou (HIRFL). Within the project of CEE, a gaseous detector is being developed for the beam monitoring. It is designed to measure the lateral position of each beam particle up to a rate of $10^{6}$ pps with a spatial resolution better than 50 $\mu$m, and with minimum interference with the beam. The beam monitor mainly consists of two field cages inside a gas vessel with electrical fields orthogonal to each other, and custom-designed charge sensing and readout chips on the anode of each field cage. Two prototypes have been developed, with upgraded charge sensor and readout system on the second one. The charge sensor integrates in the same chip the charge sensing and readout functionalities, and is intended to be used as direct charge sensor, or with the gas electron multiplier (GEM). We will present the design and test of the prototypes, with a focus on the CMOS charge sensor of the second one.

In the frame of the JINR scientific program on study of hot and dense baryonic matter a new accelerator complex Ion Collider fAcility (NICA) based on the Nuclotron-M is under realization. It will operate at a luminosity up to 1027 cm-2 s-1 for ions up to Au79+. Two interaction points are foreseen at NICA for two detectors which will operate simultaneously. One of these detectors, the Multi-Purpose Detector (MPD), is optimized for investigations of heavy-ion collisions. The Time-Projection Chamber (TPC) is the main tracking detector of the MPD central barrel. It is a well-known detector for 3-dimensional tracking and particle identification for high multiplicity events. The conceptual layout of MPD, TPC design and it’s parameters, the current status of the readout based on multiwire proportional chamber (MWPC) and readout electronics based on SAMPA chip as well as the status of TPC subsystems are presented.

NICA (Nuclotron-based Ion Collider fAсility) is a new accelerator complex designed at the Joint Institute for Nuclear Research to study properties of dense baryonic matter. Two interaction points are foreseen in the NICA collider: one for studying the collision of heavy ions on the Multipurpose detector MPD, the other for polarized beams for the experiment on the SPD installation. The ambitious physical goals of MPD require excellent particle identification at the maximum possible range of phase space. Identification of charged hadrons is achieved by combining time-of-flight measurements and dE/dx energy loss measurements from the time-projection camera TPC.

TOF will provide:

• large pseudorapidity region of |η| ≤ 1.2;
• high granularity to keep the overall system occupancy below 15%
  and minimize efficiency degradation due to double hits;
• good position resolution to ensure efficient matching of hits in the TOF system with TPC tracks;
• high geometrical efficiency and detection efficiency;
• identification of pions and kaons with pt < 1,5 GeV/c;
• identification of (anti)protons with pt < 3 GeV/c;
• function of TOF detector elements in a 0.5T magnetic field.

The time-of-flight system is based on multigap resistive plate chambers (MRPC), which are successfully used to identify particles in similar experiments around the world. A production site has been organized at the Laboratory of High Energy Physics of JINR for serial production of TOF MPD modules. This site includes the entire cycle of work from preparing materials for the assembly of detectors to testing the assembled modules on cosmic radiation.

The structure of the TOF system, its main parameters and the current state are presented. The results of decoding and processing the data obtained at the module testing facility are also presented.

A new Time-Of-Flight neutron detector for the BM@N experiment at JINR, Dubna is planned to be developed and produced. This detector will identify and measure the energies of neutrons produced in nucleus-nucleus collisions at energies up to 4 AGeV. Detector design utilizes small (40x40x25mm) scintillator tiles with solid-state readout, with timing resolution of up to 100-150ps. A small-scale prototype of the future detector is produced and tested.

Detector prototype's layout, design of mechanical structure and electronics, as well as the results of the cosmic ray tests are discussed.

Baryonic Matter at Nuclotron (BM@N) is the first experiment at the NICA accelerator complex. The aim of the BM@N experiment is to study interactions of relativistic heavy ion beams with fixed targets. Detectors based on Gas Electron Multipliers (GEM) are used of the central tracking system, which is located inside the BM@N analyzing magnet. The next BM@N physics run is planned at the end of 2022. The current installation and commissioning status of the GEM tracking system is presented.

The BM@N experiment is an ongoing fixed-target experiment launched on the extracted beam of the Nuclotron accelerator to study highly compressed nuclear matter. The forward detectors of the BM@N experiment are designed to determine the geometry of nucleus-nucleus collisions - the centrality and orientation of the reaction plane, as well as to measure the charge distributions of spectator fragments formed in nucleus-nucleus interactions. The forward detectors - the FHCal hadron calorimeter, the beam quartz hodoscope and the scintillation wall will be used for the first time in the BM@N experiment. The results of the response testing of forward detectors during the SRC (Short Range Correlation) run with carbon beam will be presented.