Description
12+3
The classicality concept is formulated. It is used to derive Wigner inequalities dependent on three instants. The possibility of testing experimentally violations of these inequalities in pure and mixed flavor states of a pair of neutral pseudoscalar mesons is studied. Within the Werner background model, it is shown that a violation of time-dependentWigner inequalities may be observed even at...
We compute the NMHV form factors of two stress-tensor operators in N=4 SYM at tree and one-loop level using unitarity methods. At tree level, we analyze the general case using the BCFW recursion and identify dual conformal symmetry properties of such form factors. In addition, we calculate the three-point form factors by the CSW recursion and perform a numerical cross-check in Mathematica,...
Monopoles and instantons play crucial roles in understanding quark confinement and chiral symmetry breaking in quantum chromodynamics. However, their relationship remains unclear. In this research, we perform Monte Carlo simulations in lattice gauge theory to identify signatures of monopoles under the influence of magnetic fields, for example, those generated in heavy-ion collision...
The QCD phase diagram at high baryon density and moderate temperature is expected to exhibit a rich phase structure beyond the possible first-order transition. Inhomogeneous phases, i. e. phases characterized by spatially modulated condensates, is one of the most intriguing options. These phases, such as the chiral density wave or crystalline condensates are studied as a rule using model...
A tensor fermionic current is the part of the Pauli Lagrangian density describing the electromagnetic interaction of fermions through their anomalous magnetic moment (AMM) induced by New Physics. Two-point vector-tensor and tensor-tensor correlators of fermionic currents are calculated in a constant homogeneous electromagnetic field background. Under assumption that this interaction enters the...
We study adjoint Wilson loops in two-dimensional Yang--Mills theory for classical, exceptional, and $\mathfrak{osp}(1|2n)$ Lie (super)algebras. The Wilson loops are evaluated numerically using the Migdal representation-sum formula and compared across different Lie families within Vogel's parametrization. Our main goal is to investigate whether this observable admits a universal description on...
We investigate a model with a gauge boson of the baryonic U(1)_B group.
Relevance: Problems of dark matter and baryon asymmetry of the Universe
Objectives:
-Construction of the Lagrangian for baryon‑photon interactions with hadrons at energy scales typical of current detectors.
-Calculation of the baryon‑photon production cross section in the main channels.
-Estimation of the parameters of...
In this talk an overview is presented of a method based on the use of exact axial anomaly relations for investigating transition form factors $\pi^0,\eta,\eta'\rightarrow\gamma\gamma^{(*)}$ in the both space- and time-like regions. This method allows to examine the nonperturbative gluon matrix element $\langle 0 |G\tilde{G}|\gamma\gamma^{(*)} \rangle$ and obtain and describe main features of...
Tetraquarks containing two bottom quarks are studied in the framework of the relativistic quark model based on the quasipotential approach and QCD. The tetraquark is considered as a bound state of a diquark and an antidiquark. The interaction quasipotential includes both spin-dependent and spin-independent relativistic contributions. The finite size of the diquark is explicitly taken into...
Recently the number of experimentally observed Υ mesons significantly increased. This opens the possibility to observe their weak decays. In this talk semi- and non-leptonic Υ decays are studied within the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The form factors are obtained and their dependence on the square of the transferred...
We revisit the decays $B^- \to \ell^+ \ell^- \bar{\nu}_{\ell'} \ell'^-$ in both $\ell \neq \ell'$ and $\ell = \ell'$ cases. Compared to our previous works, new contributions to decay parameters are investigated. Non-zero lepton masses and interference terms are fully taken into account. Excited resonances are included. The calculations are performed using the orthogonal amplitudes technique....
Neutrino oscillations probe quantum coherence over macroscopic distances and are therefore sensitive to possible environmental and beyond-Standard-Model effects. While neutrino decoherence is often introduced phenomenologically through Lindblad-type equations, its microscopic origin requires a consistent quantum field-theoretic treatment.
We present an open-system framework for neutrino...
The standard paradigm of neutrino oscillations assumes that neutrinos propagate as a coherent superposition of mass eigenstates. However, in a number
of physical scenarios — including wave packet spreading, quantum gravity effects, spacetime fluctuations, or interactions with a hot or dense medium —
this coherence can be violated, leading to the phenomenon of neutrino decoherence. Decoherence...
This paper presents a comparative analysis of the various contributions of subprocesses to the double longitudinal spin asymmetry of direct photons produced in collisions of polarized protons at PHENIX and SPD energies in the NLO approximation, which has not been considered previously. The contributions of each subprocess and all subprocesses together are presented at energies of 510 and 27...
We investigate the transverse momentum dependence of the angular distribution in the Drell-Yan process, incorporating $\gamma/Z^0$ interference in the dilepton decay. Our partonic-level analytical calculations are performed in perturbative QCD using collinear factorization at order $\alpha_s$. We analytically calculate the partonic-level T-even helicity structure functions and subsequently...
The process of $J/\psi$ production is an important probe for investigation of gluon parton distribution functions (PDFs) in proton. Though the charmonium production cross section and spectra can be satisfactorily calculated in various frameworks, another observables, such as angular coefficients in leptonic decay of $J/\psi$, do not have consistent description yet. In the present work, we...
The process of $D$-meson production is usually considered an important probe for investigating gluon parton distribution functions in the proton, as well as the heavy quark hadronization mechanism in QCD. In this report, we demonstrate that studying the angular distribution of the $D$-meson in the $D\bar{D}$-pair production can be used to check the applicability of different factorization...
We studied the production of an inclusive $\pi^0$ meson within the kinematic range,
relevant to the RHIC and the LHC colliders. We calculated the double longitudinal-spin asymmetry (DLSA)
$
A_{LL} =
\frac{d\sigma^{++} - d\sigma^{+-}}
{d\sigma^{++} + d\sigma^{+-}}
$
for the production of neutral pions in $pp$-collisions. This observable
provides reliable information on the spin-dependent...
This talk will present a common framework for indirect searches
for heavy neutral gauge bosons at the International Linear
Collider (ILC), the Compact Linear Collider (CLIC), and a muon
collider (MuC), considering their different energy stages.
The analysis will focus on virtual $Z'$ exchange in
fermion-pair production at energies below the resonance,
using a linear parametrization of...
The QCD analysis of the available data of KEDR, BESIII and CLEO Collaborations
for the e^+e^ to hadrons total cross-sections in different orders of perturbation theory is analysed. The existence of the tension between KEDR and BESIII data is emphasized with the preference to KEDR Collaboration data . The obtained values of QCD coupling constant are compared to other world average extractions...
At future NICA/SPD experiment, polarized and un-polarized proton-proton (pp), deuteron-deuteron (dd), and, possible, helium-helium (HeHe) interactions will be investigated. Therefore, Monte Carlo simulations of light nucleus-nucleus inelastic and elastic collisions are needed for designing and physical program development of the SPD experiment.
Our work is aimed to create a code for...
The variational method is used to study the energy levels of muonic helium (μ− − e− − He) with an electron in the ground state and a muon in an excited state with principal and orbital quantum numbers n ∼ l + 1 ∼ 14 (the Rydberg muon states). The variational wave functions are chosen in the Gaussian form. The matrix elements of the Hamiltonian in the nonrelativistic approximation, as well as...
The processes of leptonium production in Z-boson decay are investigated. Various decay mechanisms are examined, and relativistic decay amplitudes are constructed, taking into account the relative momenta of leptons. Decay widths are calculated for various mechanisms in the nonrelativistic approximation and taking into account relativistic corrections.
We study the longitudinal vector component of the weak vector current in nucleon and nuclear isospin doublets in order to determine the remaining last unknown longitudinal vector coupling $g_s$ of the $\beta$-decay vertex. Using the Ward identity, we establish relationships between the longitudinal form factors and the experimentally known Dirac form factors. These relations involve the scalar...
The study investigates the production of dark photons in pion-proton collisions through two mechanisms: inelastic pion bremsstrahlung and Drell–Yan-like process in the mass range 0.4–3.5 GeV.
The factorization method, previously applied to proton bremsstrahlung processes, is adapted for pion beams to overcome the limitations of chiral perturbation theory at high energies. The splitting...
Radiative QED corrections of order alpha(Z alpha)^6 to the energy spectrum of muonic hydrogen have been calculated. They are determined by the amplitudes of the three-photon exchange interaction involving one radiative photon. Nuclear structure effects arising from the expansion of electromagnetic form factors have been taken into account. An interparticle interaction potential is constructed...
Currently, a new generation of parity-violation searching experiments is planned with laser-cooled polyatomic molecules, such as the triatomic molecule RaOH. In this talk, we will examine the sensitivity of these triatomic molecules to the interactions of electrons with nuclei and electrons with electrons through single-loop exchange processes of relatively light (less than 100 keV) fermions....
