Searcharxiv⌕ Search

arXiv subjects

Yu. M. Bystritskiy

Publications and source records attributed to Yu. M. Bystritskiy.

At least 19 recordsLinked to original sources
arXiv2025

Exact calculation of photon polarization observables in Bethe-Heitler process

The effects of polarization transfer from the initial electron to the bremsstrahlung photon in electron-nucleus scattering (Bethe-Heitler process) are considered. The calculation is carried out without the assumption of smallness of the electron mass. A detailed comparison with previous well-known works is made. Some issues related to neglecting the electron mass are shown and commented on. The results are applicable to the modelling of polarized cross sections at low energies (even at a few electron mass scale).

hep-ph↗
arXiv2023

New Method for Measuring the Ratio $μ_p G_E/G_M$ Based on the Polarization Transfer from the Initial Proton to the Final Electron in the $e \vec p \to \vec e p$ Process

In this letter, we propose a new method for measuring the Sachs form factors ratio ($R =μ_p G_E/G_M$) based on the transfer of polarization from the initial proton to the final electron in the elastic $e \vec p \to \vec e p$ process, in the case when the axes of quantization of spins of the target proton at rest and of the scattered electron are parallel, i.e., when an electron is scattered in the direction of the spin quantization axis of the proton target. To do this, in the kinematics of the SANE collaboration experiment (2020) on measuring double spin asymmetry in the $\vec e\vec p \to e p$ process, using Kelly (2004) and Qattan (2015) parametrizations, a numerical analysis was carried out of the dependence of the longitudinal polarization degree of the scattered electron on the square of the momentum transferred to the proton, as well as on the scattering angles of the electron and proton. It is established that the difference in the longitudinal polarization degree of the final electron in the case of conservation and violation of scaling of the Sachs form factors can reach 70%. This fact can be used to set up polarization experiments of a new type to measure the ratio $R$.

hep-ph↗
arXiv2022

The cross section of the process $e^+e^- \to Λ\barΛ$ in the vicinity of charmonium $ψ(3770)$ including three-gluon and $D$-meson loop contributions

The total cross section of the process $e^+e^- \to Λ\barΛ$ is calculated within the energy range close to the mass of $ψ(3770)$ 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 $Λ$-hyperon is obtained for the large momentum transferred region.

hep-ph↗
arXiv2021

The cross section of the process $e^+e^- \to p\bar{p}$ in the vicinity of charmonium $ψ(3770)$ including three-gluon and $D$-meson loop contributions

The total cross section of the process $e^+e^- \to p\bar{p}$ is calculated within the energy range close to the mass of $ψ(3770)$ charmonium state. It was shown that the main contribution to this cross section comes from three gluon mechanism which is also responsible of the large phase with respect to the Born amplitude. This phase provides the characteristic dip behaviour of the cross section in contrast to the usual Breit-Wigner peak shape. OZI-allowed mechanism with D-mesons in the intermediate state was also estimated and gives relatively small contribution to the cross section and to the phase.

hep-ph↗
arXiv2019

Radiative corrections in proton--antiproton annihilation to electron-positron and their application to the PANDA experiment

Radiative corrections to the annihilation of proton--antiproton into electron--positron are revisited, including virtual and real (soft and hard) photon emission. This issue is relevant for the time-like form factors measurements planned at the PANDA experiment at the FAIR facility, in next future. The relevant formulas are given. A stand-alone Monte-Carlo integrator is developed on the basis of the calculated radiative cross section and its application to the PANDA experiment is illustrated.

hep-ph↗
arXiv2017

Low and High Energy Asymptotic Behavior of Electroweak Corrections in Polarized $e^+ e^- \to μ^+ μ^-$ Process

Electroweak radiative corrections will play a major role in the analysis of several upcoming ultra-precision experiments such as Belle-II, so is crucial to make sure that they are fully under control. The article outlines the recent developments in the theoretical and computational approaches to one-loop (NLO) electroweak radiative corrections to the parity-violating asymmetry in $e^- e^+ \to μ^- μ^+ (γ)$ process with longitudinally polarized electrons. We derive asymptotic expressions for low and high energy regions (well below or above $Z$-resonance, correspondingly) and analyze the leading contributions. For most of energy regions, our results are in good agreement with precise computer-algebra based calculation and can used as a quicker alternative.

hep-ph↗
arXiv2015

Two-loop electroweak vertex corrections for polarized Møller scattering

The contributions to the electron-electron-photon vertex of two-loop electroweak corrections are calculated. The relative correction to the parity-violating asymmetry of Møller scattering for the case of 11 GeV electron scattered off the electron at rest is found to be about -0.0034 and should be taken into account at future experiment MOLLER at JLab.

hep-ph↗
arXiv2015

NNLO electroweak corrections for polarized Moller scattering: one-loop insertions to boxes

The paper discusses the two-loop (NNLO) electroweak radiative corrections to the parity-violating Moller scattering asymmetry induced by insertions to boxes of electron and neutrino mass operators (fermion self-energies), vertex functions and boson self-energies. The results will be relevant to the ultra-precise 11 GeV MOLLER experiment planned at the Jefferson Laboratory, which will measure the weak charge of the electron and search for new physics. The numerical estimations for the NNLO contribution to the cross section asymmetry are presented.

hep-ph↗
arXiv2014

About the creation of proton-anti-proton pair at electron-positron collider in the energy range of the mass $Ψ(3770)$

The process of electron--positron annihilation into proton--antiproton pair is considered within the vicinity of $ψ(3770)$ resonance. The interference between the pure electromagnetic intermediate state and the $ψ(3770)$ state is evaluated. It is shown that this interference is destructive and the relative phase between these two contributions is large ($ϕ_0 \approx 250^o$).

hep-ph↗
arXiv2013

Radiative corrections for electron proton elastic scattering taking into account high orders and hard photon emission

We investigate the effect of high order radiative corrections in unpolarized electron proton elastic scattering and compare with the calculations at lowest order, which are usually applied to experimental data. Particular attention is devoted to the $ε$ dependence of radiative corrections, which is directly related to the electric proton form factor. We consider in particular the effects of the interference terms for soft and hard photon emission. Both quadratic amplitude describing the collinear emission along the scattered electron as well as the interference with the amplitudes of emission from the initial electron and the emission from protons are important in leading and next to leading approximation and they may compensate in particular kinematical conditions.

hep-ph↗
arXiv2013

Two-pion production in electron-polarized proton scattering

The process of two pion production in the electron-polarized proton scattering is investigated. In the Weizsäcker-Williams approximation the differential spectral distributions and the spin-momentum correlations are considered. The spin correlation effects caused by $ρ$-meson widths are estimated to be of an order of several per cent. Both channels of the $π^+π^-$ and $π^+π^0$ creation are considered. The effects of intermediate excited baryons are not considered. The spectral distributions on pion energy fractions in polarized and unpolarized cases are presented analytically and numerically.

hep-ph↗
arXiv2013

On the measurement of $χ_2(^3P_2)$ quarkonium state in the processes $e^++e^-\to \bar p+p$ and $\bar p+p\to e^++e^-$

The intermediate quarkonium state $χ_2(^3P_2)$ in electron-positron annihilation to proton and antiproton as well as in antiproton-proton annihilation to electron and positron can produce backward-forward asymmetry, when populated through two photon exchange. We use the dispersion relation method, which permits to express the asymmetry in terms of partial widths of quarkonium decay. The asymmetry dependence on the center of mass energy in the range near the resonance is presented. The comparison with a similar effect in these reactions with the neutral $Z$-boson in the intermediate state is given. We show that these effects are $\le 10^{-3}$. The main source of asymmetry is of pure QED origin ($\sim 10^{-2}$) which arises from the interference between initial and final state real photon emission.

hep-ph↗
arXiv2012

A new conception in describing the Drell-Yan type processes

A set of evolution equations for correlators of densities of quark and gluons is considered. Approximate solutions is obtained in frames of gluon and quark dominance. A new formulation of the cross sections of Drell-Yan process is suggested. Differential cross sections for the QCD sub-processes of type $2 \to 2$ are obtained. Sub-process $g b\to tH^-$ as well considered.

hep-ph↗
arXiv2012

Parity violating Moller scattering asymmetry up to the two-loop level

The paper investigates contributions of $Z$, $W$ and $γ$ intermediate states to the parity-violating Moller scattering asymmetry up to two-loop level. Using the Yennie--Frautschi--Suura factorization form for amplitudes, we demonstrate that QED corrections, with an exception of vacuum-polarization effects, cancel at the asymmetry level. We obtain chiral amplitudes at Born, one-loop and partially at two-loop level: boxes with lepton self-energies, ladder boxes and decorated boxes. Our calculations are relevant for the ultra-precise 11 GeV MOLLER experiment planned at Jefferson Laboratory and future ILC experiments. The numerical comparision of the two-loop contributions with the experimental accuracy of MOLLER is provided.

hep-ph↗
arXiv2012

Annihilation of $\bar p+p\to e^++e^-+ π^0$ and $\bar p+p\to γ+ π^0$ through $ω$-meson intermediate state

The s-channel annihilation of proton and antiproton into a neutral pion and a real or virtual photon followed by lepton pair emission is studied. Such mechanism is expected to play a role at moderate values of the total energy $\sqrt{s}$, when the pion is emitted around $90^{\circ}$ in the center of mass. A fair comparison with the existing data is obtained taking into account scattering and annihilation channels. The cross section is calculated and numerical results are given in the kinematical range accessible in the PANDA experiment at FAIR.

hep-ph↗
arXiv2012

One-loop chiral amplitudes of Moller scattering process

The high energy amplitudes of the large angles Moller scattering are calculated in frame of chiral basis in Born and 1-loop QED level. Taking into account as well the contribution from emission of soft real photons the compact relations free from infrared divergences are obtained. The expressions for separate chiral amplitudes contribution to the cross section are in agreement with renormalization group predictions.

hep-ph↗
arXiv2011

Peripherical processes 2 $\to$ 3 and 2 $\to$ 4 in QED and QCD in $p(\bar p)p$ high energy collisions

Differential cross section of processes with high energy $p(\bar p)p$ collisions in frames of QED: creation of scalar, pseudoscalar and lepton pair - are considered in Weizsäcker - Williams approximation. In frames of QCD processes with conversion of initial proton (antiproton) to fermionic jets accompanied with one gluon jet as well as the state of two gluons and quark-antiquark pair (with out rapidity gap) are considered in frames of effective Reggion action of theory of Lipatov. Process of creation of a Higgs boson accompanied with two fermionic jets is considered. The azimuthal correlation in process of two gluon jet separated by rapidity gap is investigated. Effects of gluon reggeization are taken into account. Some distributions are illustrated by numerical calculations.

hep-ph↗