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O. Voskresenskaya

Publications and source records attributed to O. Voskresenskaya.

At least 19 recordsLinked to original sources
arXiv2026

Deser formula for the shift of energy levels of hadronic atoms in terms of the effective radius of the strong interaction with the Coulomb wave function of hadronic atoms at the origin

It is shown that the relations between probabilities of A_2π-atoms creation in ns-states, derived with neglecting of strong interaction between pions, remain practically unchanged if the strong interaction is taken into account in the first order of perturbation theory. The formulation of Deser equation for the energy shift of energy levels of hadronic atoms is given in terms of the effective range of strong interaction and the relative correction to the Coulomb wave function of hadronic atoms at the origin, caused by the strong interaction.

hep-ph↗
arXiv2026

Accuracy, asymptotes, and applications of the Born approximations to the calculation of the Mott scattering cross section, the primary atomic displacement cross section, and the energy-loss straggling

The first, second and third Born approximations of the Mott scattering cross section are considered. The relative error of all three Born approximations averaged by angles and energies is calculated for the first 30 elements of the Mendeleev periodic table of elements and also of the second and third-Born approximation for the first hundred elements of the Mendeleev table. The accuracy of the second and third Born approximations for calculating the normalized Mott scattering cross section are compared on the wide range of nuclei of elments. The accuracy of the Born approximations for calculating the Mott correction in the Bethe-Bloch formula for for the second Born approximation and the third approximation is analyzed. An expression is obtained for the cross section of the primary displacement of the atom in the third Born approximation. For iron, silver and lead, the cross section of the primary displacement of the atom for a number of electron energies is calculated. For a number of examples, it is calculated starting from the electron energy. The difference of the cross section is obtained by the asymptotic formula from by the McKinley-Feshbach formula, it will be less than one percent. Accuracy of the Born approximations for calculating energy-loss straggling is analyzed.

nucl-th↗
arXiv2020

Corrections to the Bethe formula for average ionization energy loss of relativistic charged particles in solids. I. Mott's corrections

Based on the proposed representation of the Mott corrections to the Bethe stopping formula in the form of rapidly convergent series of quantities bilinear in the Mott partial amplitudes, the numerical calculations were performed for these corrections over a wide range of nuclear charge number of the incident particles at various values of their relative velocity.

nucl-th↗
arXiv2018

Corrections to the higher moments of the heavy ion energy-loss distribution beyond the Born approximation. II. Beta dependence of Mott's corrections

The Mott corrections to the higher moments of the heavy ion energy-loss distribution are calculated in a wide range of relative particle velocity on the basis of the Mott exact cross section. It is shown that the relative Mott corrections to the first-order Born central moments and normalized central moments reach a large value over the range under consideration.

hep-ph↗
arXiv2016

Dimesoatoms production in high energy collisions

The production of two meson electromagnetic bound states and free meson pairs $π^+π^-$, $K^+K^-$, $π^+ K^{\mp}$ in relativistic collisions has been considered. It is shown that making use of the exact Coulomb wave function for dimesoatom (DMA) allows one to calculate the yield of any nS state with desired accuracy. The relative probabilities of production of DMA and meson pairs in the free state are estimated. The amplitude of DMA transition from 1S to 2P state, which is essential for the pionium Lamb shift measurements, has been obtained.

hep-ph↗
arXiv2014

An improvement of the Moliere-Fano multiple scattering theory

In the framework of unitary Glauber approximation for particle-atom scattering, we develop the general formalism of the Moliere-Fano multiple scattering theory (M-F theory) on the basis of reconstruction of the generalized optical theorem in it. We present rigorous relations between some exact and first-order parameters of the Moliere multiple scattering theory, instead of the approximate one obtained in the original paper by Moliere. We consider the relative unitarity corrections and the Coulomb corrections to the quantities of the M-F theory. Also, we examine their Z dependence in the range of nuclear charge, from Z=4 to Z=92. Additionally, we show the difference between our results and those of Moliere over this Z range.

hep-ph↗
arXiv2014

Moliere's multiple scattering theory revisited

A part of Moliere's multiple scattering theory concerning the determination of the screening angular parameter is revised. An universal form of the Coulomb corrections to the screening angle, the exponential part of the distribution function, and the angular distribution is discussed within the small-angle approximation of this theory. The accuracy of the Moliere theory in determining the screening angle is estimated.

hep-ph↗
arXiv2014

Coulomb Corrections to the Parameters of the Landau-Pomeranchuk-Migdal Effect Theory and its Analogue

Using the Coulomb correction to the screening angular parameter of the Moliere multiple scattering theory, we obtained analytically and numerically the Coulomb corrections to the parameters of the Migdal LPM effect theory. We showed that these corrections allow to eliminate the discrepancy between the predictions of the LPM effect theory and its measurement at least for high Z targets and also to further improve the agreement between the predictions of the LPM effect theory analogue for a thin layer of matter and experimental data.

hep-ph↗
arXiv2011

Determination of $ππ$ scattering lengths from measurement of $π^+π^-$ atom lifetime

The DIRAC experiment at CERN has achieved a sizeable production of $π^+π^-$ atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave $ππ$ scattering length difference $|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{π^+}^{-1}$ has been attained, providing an important test of Chiral Perturbation Theory.

hep-ex↗
arXiv2006

Form Factors of Dimesoatoms for Discrete-Continuum Transitions

An approach for calculation of transition form factors of hydrogen-like elementary atoms (EA) is proposed. A general formula for bound-continuous transition form factors of EA is derived. It is shown that these form factors can be represented in the form of finite sum of terms with simple analytical structure and may be numerically evaluated with arbitrary degree of accuracy. As an application of the presented form factors, the calculation of the spectra of products from EA ionization is considered.

nucl-th↗
arXiv2002

Contribution of $α^2$-terms to the total interaction cross sections of relativistic elementary atoms with atoms of matter

It is shown that the corrections of $α^2$ order to the total cross sections for interaction of elementary hydrogen-like atoms with target atoms, reported in the previously published paper [S.Mrowczynski, Phys.Rev. D36, 1520 (1987)], do not include some terms of the same order of magnitude. That results in a significant contribution of these corrections in particular cases. The full $α^2$-corrections have been derived and it is shown that they are really small and could be omitted for most practical applications.

hep-ph↗
arXiv1999

The eikonal approach to calculation of the multiphoton exchange contributions to the total cross sections of π^+pi^- atom interaction with ordinary atoms

The total cross sections of interaction of relativistic π^+π^- atom with ordinary atoms are obtained in the eikonal approach, which takes into consideration all multiphoton exchange processes. Contribution of these processes strongly depends on the atom nucleus charge Z and varies from 1.5% for Titanium (Z=22) to 14% for Tantalum (Z=73)

hep-ph↗
arXiv1998

A method for research on behaviour of a dimesoatomic wave function at small distances

The Schrödinger equation discribing the local potential model of a strong $π^+π^-$-interaction was studied. The influence of the strong $π^+π^-$-interaction of the behaviour of pionium nS-state wave functions at small distances is studied both analytically (perturbatively) and numerically. It is shown that in the whole the accounting of strong interaction results in multiplying pure Coulomb pionium wave functions by some function is practically independent of the value of the principal quantum number n. Due to this reason, the n-independence of probability of $π^+π^-$-atom production in nS-state remains the same as in the case of a pure Coulomb $π^+π^-$-interaction.

hep-ph↗
arXiv1998

The Influence of Strong Interaction on the Pionium Wave Functions at Small Distances

The influence of strong $π^+π^-$ interaction of the behaviour of pionium nS-state wave functions at small distance are investigated both analytically (perturbatively) and so numerically. It is shown that in the whole the accounting of strong interaction results in multiplying of pure Coulomb pionium wave functions by some function practically independent on value of principal quantum number n. Due to this reason the n-independence of probability of $π^+π^-$ atom production in nS-state remains the same as in case of pure Coulomb $π^+π^-$ interaction

hep-ph↗