Search and study of exotic hadrons - tetraquarks and pentaquarks - is one of topical problems in modern high energy physics. To determine spin-parity of these states, test theoretical predictions of their spectra and reveal the internal structure - high-precision measurements of their parameters are required. Amplitude analysis is a recognized tool for solving this problem. In this report, the...
The purpose of the present work is calculation of the cosmological perturbation spectrum in a flat model with a scalar field in the slow-roll regime. Mukhanov’s gauge-invariant approach for calculating the spectrum of gravitational perturbations is analyzed. In contrast to Mukhanov’s paper [1] we calculate perturbation spectrums of gravitational and scalar fields separately. We use action of...
Cosmic rays with energies above $10^{19}$eV, observed in 1999 - 2004 by the High Resolution Fly's Eye (HiRes) experiment in the stereoscopic mode [1], were found to correlate with directions to distant BL Lac type objects (BL Lacs, which constitute a subclass of blazars, are active galactic nuclei with jets pointing to the observer), suggesting non-standard neutral particles travelling for...
The paper presents a clarified database of the parameters of beta-active nuclei, which includes previously unknown and inaccurately estimated parameters. The parameters were obtained by using our developed method of converged sequence of calculated energy spectra to the resulting spectrum, which is most close to the experimental one. Rovno experimental spectrum was taken as the experimental...
In this paper, we propose a method that makes it possible to use an ultrathin calorimeter for direct measurements of cosmic rays with energies of TeV and higher. The problems of determining the primary energy with a thin calorimeter, due to large fluctuations in shower development, the low statistics of analyzed events and the large size required for the calorimeter, are considered in detail....
The NOvA experiment aims to study neutrino oscillation parameters using an accelerator complex. Far detector big size and high segmentation structure as well as a flexible system of software triggers and data acquisition allows to detect the atmospheric neutrinos and study their parameters in NOvA.
This work presents the developed technique of atmospheric neutrinos registration in the far...
In this paper, a set of programs is presented that allow obtaining angular distributions. For testing, the reaction 10В(7Li, 6Li)11В was used at an incident beam energy of 58 MeV. The experiment was done using the U-400 accelerator beam of the FLNR JINR, Dubna. One of the goals of the experiment was to study the excited states of the 11B nucleus. The obtained differential cross sections are...
The MPD detector at the NICA facility is under construction. One of the key subsystems of the MPD experiment is the electromagnetic calorimeter ECal. The ECal modules are calibrated using cosmic muons. Signal from SiPM of each tower is digitized by the ADC in a 640 ns window. The purpose of the calibration procedure is to establish a correct relation between the measured signal and real energy...
The results of a study of detectors made of silicon carbide (SiC) and silicon (Si) are presented. The irradiation was carried out using exemplary spectrometric α-sources with energies $E = 4.8 - 7.7$ MeV. The thickness of the epitaxial layer of the n-type SiC detectors was 25 and 50 microns, with a contact diameter of 3.0 mm. The initial energy resolution of the detectors was <25 keV. Si...
The study of the momentum spectra of charged particles allows one to obtain information about the thermodynamic characteristics of system arising from the collision of heavy ions. This research can improve the understanding of their interactions and dynamics in various physical processes.
The aim of this work is to study the momentum spectra of pions, kaons, and protons in Ar+Ar and p+p at...
We consider axion-like particle (ALP) model to construct numerical spatially homogeneous anisotropic Kantowski-Sachs cosmological model. We present our first-step approximation on analysis of the background' dynamics of domain wall, induced by ALP scalar field. We consider limiting case far from the wall itself, yet we found non-trivial behaviour of the space-time.
Inflationary expansion is one of the most promising models allowing one to describe the properties of the early Universe and its later development. In the simplest realisation of the inflationary scenario, it is generally assumed that after the Universe leaves the inflationary stage and post-inflationary reheating, it remains at minimum potential with a value of $\Lambda \sim 10^{-47}$...
Background radiation estimation is an important part of the process of planning and conducting experiments in high energy physics. The aim of this work is not only to calculate radiation doses for the safe conduct of the new short-range correlations experiment using Geant4, but also to compare with the results obtained using FLUKA.
The Tokai-to-Kamioka (T2K) [1] is a flagship long-baseline accelerator experiment located in Japan. T2K is designed to measure neutrino oscillation parameters and further probe CP violation in the lepton sector of the Standard Model. The near detector ND280 [1] is an essential part of the experimental facility. The detector studies various interaction channels, the flavor content and energy...
The isotropic light source for calibration of liquid scintillator neutrino detectors has been developed. The Monte Carlo simulation was performed to optimize its design. The satisfactory version of the source design was chosen. And the source was produced. It is currently being tested in the TAO detector. Also, the report covers the development of a primary particle generator which is able to...
A Focusing Aerogel RICH detector (FARICH) detector is a valuable component of the particle identification system in the SPD experiment, improving the separation of pions and kaons in final open charmonia states (momenta below 5 GeV/c). High event rate resulting from a free-running (triggerless) data acquisition pipeline of the SPD necessitates the development of a rapid, robust software event...
The phenomenon of neutrino oscillations emerges due to coherent superposition of neutrino mass states. An external environment can modify a neutrino evolution in a way that the coherence will be violated. Such violation is called quantum decoherence of neutrino mass states and leads to the suppression of flavor oscillations. In our previous paper [1] we presented a new theoretical framework,...
Neutron response function of CeBr3 detector for
1.25-5.75 MeV neutron energy range.
Povolotskiy M.A.1,2, Sobolev Yu.G.1, Stukalov S.S.1, Bezbakh A.A.1,
Penionzhkevich Yu.E.1,2, Salakhutdinov G.Kh2, Naumov P.Yu2
1 JINR, Joint Institute for Nuclear Research, 141980, Dubna, Russia;
2 MEPhI, National Research NuclearUniversity,115409, Moscow, Russia;
E-mail:...
Theoretical and experimental investigations of neutron-rich nuclei represent one of the most fascinating and abundant sources of new information about nuclear structure. The varied properties of atomic nuclei impose significant requirements on theoretical approaches. One of the most effective microscopic methods for investigating ground-state properties is the Hartree-Fock (HF) approach, which...
We give a decomposition of the vector current matrix element, and present our analysis and study for the generalized parton distribution functions (GPDs) of spin-3/2 systems [1]. Sum rules of those GPDs and the structure functions of the systems are discussed. As a typical example, we numerically calculate the electromagnetic and gravitational form factors of the spin-3/2 baryons (like...
At the present time, a scintillation material $^6$Li$_2$CaSiO$_4$:Eu$^{2+}$ (LCS) is being developed at the NRC “Kurchatov Institute”. This material is designed for neutrons registration by capturing by the $^6$Li isotope. The work presents the possibility of using LCS for neutrons detection after the inverse beta decay reaction ($\bar{\nu_e} + p \rightarrow n+e^{+}$), which is widely used for...
The MPD detector at the NICA facility is under construction. One of the key
subsystems of the MPD experiment is electromagnetic calorimeter ECal.
Modules of the ECal undergo calibration using cosmic muons now. These data
were used for parameterization of the digitized SiPM signals after low pass
filter at an input of ADC. Few models of SiPM signals were tried and the
best one was found. The...
In case of diboson production in pp collisions there is a non-negligible possibility that some events passing the final selection in data are actually from multiple overlapping hard-scatter processes occurring within the same bunch-crossing. Such events with combination of two processes associated with different primary vertices corresponds to so-called pile-up background. Its contribution...
The physics of positrons becomes crucial when working with radioactive isotopes like Fluorine-18, which has a proton-rich nucleus and, therefore, an excess of energy that is released by emitting positrons and neutrinos. Fluorine-18 has important applications in medical diagnostics due to its similarity to the hydrogen molecules in the human body, especially when combined with the drug...
When designing X-ray telescopes, it is essential to consider interference that may occur on the detectors. For instance, in many current telescopes, such as eROSITA from the Spectrum-Roentgen-Gamma (SRG) project, a system of magnets is positioned after the mirror assembly, which focuses particles. This magnet system is designed to deflect electrons and protons. It can deflect protons with...
The NA64 experiment at the CERN SPS is designed to search for dark photons in events with missing energy. The most studied production mechanism is dark Bremsstrahlung through a vector mediator. Bremsstrahlung photons can convert to hard vector mesons in exclusive photoproduction processes, which then decay to dark matter (DM). The vector meson decays invisibly to DM via mixing with the dark...
The DANSS detector is placed under the reactor core of Kalinin NPP (at distances 10.9–12.9 m) and collects up to 5000 antineutrino events per day. One of the main goals of the experiment is to scrutinize the sterile neutrino hypothesis. A large fraction of allowed parameter space was excluded by DANSS: for some values of Δm$^2$, the exclusion goes up to $\sin^2(2\theta)<0.01$, which had become...
Bosonic dark matter search results with neutrino detector iDREAM at Kalinin Nuclear Power Plant are presented. Using accurate data on composition of the active core of VVER-1000 nuclear reactor and fission fractions of primary fissile isotopes, the $\gamma$-radiation energy spectrum in the active core is calculated. Assuming that the dark bosons can be produced in the active core via...
The semi-inclusive deep inelastic scattering (SIDIS) of a lepton on a polarized proton provides a means of studying the internal structure of the proton. This scattering gives an observable, the Sivers asymmetry, which can be measured for positive and negative pions productions within the scattering event. This measurement allows access to the Sivers parton distribution function (PDF).
In...
In 2019, as part of the development of the TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma Astronomy) astrophysical complex, construction of the TAIGA-Muon scintillation facility began in addition to the existing Tunka-Grande system. The main objective of these systems is to study the energy spectrum and mass composition of cosmic rays in the energy range of $10^{15}–10^{18}$ eV, as...
By periodically varying the temperature of a pyroelectric single crystal under vacuum conditions, a compact charged particle accelerator can be created [1]. In addition to the single crystal, this also requires a grounded target, which acts as the second electrode in the acceleration scheme. This type of accelerator can be described as quasi-electrostatic. In various modes, this compact device...
The light nuclei 12C and 6Li used as target and projectile nuclei in the many experimental studies of the nuclear reactions, including Flerov Laboratory of Nuclear Reaction (JINR). The study of the structure of these nuclei is necessary for theoretical description of such reactions. Wave functions of the ground state of the 12C and 6Li nuclei in the alpha-cluster model are calculated using...
The SuperFGD (Super Fine-Grained Detector) is a part of ND280 near
detector complex for T2K and Hyper-Kamiokande experiments. The
SuperFGD is a fully active and highly granular scintillator neutrino
detector. It consists of ∼2 million scintillation cubes, which allow
reconstruction of particles going in all directions. A good
understanding of SuperFGD response is crucial for detailed...
The minimum analytical model describing the neutrino radiation at conditions of core-collapse supernova, is considered. We find that such model contains four parameters. Each of these parameters depends on the radial coordinate and time. In addition, the numerical values of individual parameters have a large spread of values and significantly depend on the hydrodynamics of the explosion. Thus,...
The Large Volume Detector located in the Gran Sasso Laboratory, Italy, has been operating in the stellar core collapse neutrino search program since 1992. Based on 32 years of detector data, an experimental constraint on the frequency of neutrino bursts from gravitational collapses of stars in the Galaxy has been obtained: less than 1 event in 13.9 years at a 90% confidence level. At an...
This report shows how the current models of reactor antineutrino energy spectra affect the estimates of the count rate for coherent elastic neutrino-nucleus scattering (CE$\nu$NS) in the RED-100 experiment. The reactor antineutrino spectrum consists of contribution from 4 main (parent) isotopes $^{235}U$, $^{238}U$, $^{239}Pu$, $^{241}Pu$, taken with partial coefficients on the burn-up moment....
The Wheeler–DeWitt geometrodynamics, which was the first attempt to develop a quantum theory of gravity, faces some problems, such as the problem of time or the interpretation of the wave function. In this work, as an alternative to Wheeler–DeWitt quantum geometrodynamics, we consider the extended phase space formalism. Within this framework, one can derive the Schrödinger equation, which...
The main goal of the NA64 experiment is searching for sub-GeV dark matter production mediated by a dark photon A' or light dark boson Z'. Dimuons are used to check the accuracy of the Monte-Carlo simulation of the NA64 setup based on the Geant4 package. They also represent a background source in the dark sector search.
For further investigation of neutrino oscillations in the T2K
experiment, a 3D segmented SuperFGD detector is constructed. It
consists of 2 million scintillation cubes of 1 cm3 size, with wavelength-
shifting (WLS) fibers along three orthogonal directions. Each fiber is read
out by a Hamamatsu Multi-Pixel Photon Counter S133060-1325PE. The
detector main goals are to reduce systematic...
We present a further development of the Modified Monte Carlo Glauber model (MGM) [1],[2], which takes into account at the given impact parameter of heavy nuclei interaction, for each nucleon, the fraction (k) of energy loss, arising during the consecutive inelastic nucleon-nucleon collisions due to multiple production of particles. The one-parameter model also takes into account, at each...
G.A. Askaryan had shown in 1960s [1,2] that the interaction of high-energy particles with the rather dense dielectric medium should form the negative charged cascades moving with superluminal velocity in the medium. This Askaryan’s effect is laid on the basis of the radio-astronomical method for detecting ultra-high-energy neutrinos, proposed later by R.D.Dagkesamansky and I.M. Zheleznykh...
Superfluid He-4 can serve as a tool for neutrino [1] and dark matter detection [2]. Low-energy neutrino interaction with superfluid He-4 can take place in the form of coherent elastic neutrino-atom scattering (CEvAS) [3] - a process that has not been observed so far. The first experimental study of CEvAS is under preparation in the National Center for Physics and Mathematics in Sarov [4]....
For experiments on searching for rare underground events, such as detection of solar neutrinos, neutrinos from supernovae, neutrinoless beta decay, the main problem is the background variation. Regardless of the detector power supply, two types of backgrounds can be specified: muons and natural radioactivity of construction materials, rock, as well as a variable component of radioactivity -...
Detectors based on organic crystals of trans-stilbene and paraterphenyl are the most effective for simultaneous registration of mixed gamma-neutron fields in the range of 0.1 – 20 MeV, which is an integral part of scientific and dosimetric measurements in nuclear power engineering and nuclear medicine. Currently, organic crystal detectors are not mass-produced in Russia, although in the...
Method of measurement and result of processing of the 213Po α-active isotope half-life data measured in long-run continuous measurement with the underground low-background TAU-3 set-up are described. The set-up consists of two scintillation NaI(Tl) 150x150 mm detectors and double-layer (hlayer=1 mm) plastic scintillator detector (PCD) with d=18 mm. Source of the ...213Bi→213Po… decays placed...
The main reaction used to detect Core-collapse Supernova neutrinos in physical experiments is the inverse beta decay reaction. Positrons produced in the reaction pass through a scintillator only a few centimeters thick. For the Baksan Underground Scintillation Telescope (BUST) detector, which has a modular structure, the inverse beta decay reaction appears as a single trigger of an individual...
We consider applications of the deformation procedure to two-soliton solutions of the sine-Gordon model. We analyze the resulting kink-antikink configurations of other field-theoretical models.
The project assumes that in one installation two traps are installed on the same axis: material and magnetic. By rotating the trap system around an axis, it is possible to carry out gravitational capture of UCNs either into a material or into a magnetic trap. Thus, on one installation it is possible to compare the material and magnetic storage of UCNs under the same conditions. It is also...
The deuteron-proton elastic scattering process is considered in the relativistic
expansion framework. Four reaction mechanisms are taken into account: one-nucleon exchange,
single-scattering, double-scattering terms, and term with delta-isobar in the intermediate state.
Each of these mechanisms contributes into the reaction amplitude. The calculations for the
differential cross section and a...
Recent multi-messenger observations suggest that high-energy neutrinos may be produced close to central black holes in active galaxies. These regions may host dark-matter (DM) spikes, where the concentration of DM particles is very high. Here we explore the contribution of the DM annihilation to the target photons for the neutrino production, proton-photon interactions, estimate the associated...
Scintillation detectors are successfully used to register fast neutrons in the presence of background gamma radiation. However, when scintillation detectors operate near particle accelerators, a problem arises due to the presence of a magnetic field near the accelerator.
In this paper we investigate the influence of the magnetic field of the HELIS accelerator facility on the parameters of...
The problem of diagnostics of electron reaction products obtained in experiments on particle acceleration by a laser field was solved. Accelerated electrons were obtained by the interaction of a laser pulse with a flowing gas target. The central wavelength of the laser pulse is 800 nm, the duration is about 50 fs, and the repetition rate is 10 Hz. The energy on the target reaches 60 mJ. Due to...
An simulation for two main reactions of fast neutron and boron-10 inteaction in anode wire coating
of gas-discharge tube counter is performed.
Moving of secondary nuclei ${^4}He$ и ${^7}Li$ within coating is considered.
Residual energy of nuclei is calculated taking into account reaction kinematics.
It was found that a condition for a both nucleus exit from anode to counter gas must...
The results of measurements of charge losses at detection of heavy xenon ions with detectors based on boron carbide (SiC) and silicon (Si) are presented. It is shown that the measured values of charge losses (amplitude defect) from the true energy of Xe ions for Si and SiC detectors are 20 and 40%, respectively. These results are due to the significantly shorter lifetime of charge carriers...
