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A. V. Eskin

Publications and source records attributed to A. V. Eskin.

14 recordsLinked to original sources
arXiv2026

Rydberg states of muonic helium in quantum electrodynamics

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 $n \sim l+1 \sim 14$. The variational wave functions are chosen in the Gaussian form. The matrix elements of the Hamiltonian in the nonrelativistic approximation, as well as corrections for the vacuum polarization and relativism, are calculated analytically. A series of energies of the Rydberg muon states is obtained, which can be studied experimentally.

hep-ph↗
arXiv2026

Few-particle lepton bound states in variational approach

The energy levels of the ground states of the three-particle and four-particle bound states of leptons in quantum electrodynamics are calculated. For the calculation, the variational method with Gaussian basis functions is used. The hyperfine structure of the spectrum is taken into account due to the pairwise spin-spin interaction of particles.

hep-ph↗
arXiv2025

Production of dileptonic bound states in the Higgs boson decay

The production of single and paired lepton bound states in the decay of the Higgs boson has been studied. We explore different decay mechanisms that contribute significantly to the decay width. The decay widths are calculated taking into account relativistic corrections in the decay amplitude and in the wave function of the bound state of leptons.

hep-ph↗
arXiv2025

Heavy tetraquarks in the hyperspherical approach

Within the quark model and hyperspherical method, the bound states of four heavy quarks and antiquarks (tetraquarks) are investigated. In hyperradial approximation, the Schroedinger equation is reduced to a one-dimensional equation after averaging over angles in hyperspace. This equation is solved numerically and analytically within the variational method. The hyperfine structure of the spectrum is calculated. To increase the accuracy of the calculation, corrections to the energy levels from the QCD generalization of the Breit Hamiltonian are taken into account.

hep-ph↗
arXiv2025

Production of heavy tetraquarks in rare exclusive decays of the Higgs boson

The relativistic quark model is used to study the processes of heavy tetraquark $(cc\bar{c}\bar{c})$ production in the Higgs boson decay. We consider quark-gluon, ZZ-boson, and quark-gluon loop decay mechanisms with the production of a fully charmed tetraquark. Relativistic interaction amplitudes are constructed and decay widths are calculated taking into account relativistic corrections in the decay amplitude connected with the relative motion of quarks and antiquarks.

hep-ph↗
arXiv2025

Mass spectrum of heavy tetraquarks in variational approach

Within the framework of the quark model and the variational method, the bound states of four heavy quarks (tetraquarks) are investigated. The basis variational wave functions are chosen in the Gaussian form. The matrix elements of the Hamiltonian are calculated analytically. Numerical calculation of the energy levels of tetraquarks is performed using a program in the Matlab system. Hyperfine structure of the spectrum is calculated. To increase the accuracy of the calculation, relativistic corrections are taken into account.

hep-ph↗
arXiv2025

Production of heavy quark bound states in rare exclusive decays of Higgs boson

The processes of pair production of S- and P- wave charmonium, as well as the production of the tetraquark (cc \bar{c} \bar{c}) in the Higgs boson decays are investigated within the framework of relativistic quark model. Relativistic decay amplitudes are constructed and decay widths are calculated taking into account relativistic corrections both in the decay amplitude and in the wave function of bound heavy quarks.

hep-ph↗
arXiv2024

Hadronic light-by-light scattering contribution to 1S-2S transition in muonium

We study hadronic light-by-light scattering contribution to the energy interval (1S-2S) in muonium. Various amplitudes of interaction of a muon and an electron are constructed, in which the effect of hadronic scattering of light-by-light is determined using the transition form factor of two photons into a meson. Their contributions to the particle interaction operator in the case of S-states are obtained in integral form, and to the energy spectrum in numerical form. The contributions of pseudoscalar, scalar, axial vector mesons are taken into account.

hep-ph↗
arXiv2023

Contribution of hadronic light-by-light scattering to the hyperfine structure of muonium

The contribution of hadronic scattering of light-by-light to the hyperfine structure of muonium is calculated using experimental data on the transition form factors of two photons into a hadron. The amplitudes of interaction between a muon and an electron with horizontal and vertical exchange are constructed. The contributions due to the exchange of pseudoscalar, axial vector, scalar and tensor mesons are taken into account.

hep-ph↗
arXiv2023

Energy levels of mesonic helium in quantum electrodynamics

On the basis of variational method we study energy levels of pionic helium $(π-e-He)$ and kaonic helium $(K-e-He)$ with an electron in ground state and a meson in excited state with principal and orbital quantum numbers $n\sim l+1\sim 20$. Variational wave functions are taken in the Gaussian form. Matrix elements of the basic Hamiltonian and corrections to vacuum polarization and relativism are calculated analytically in a closed form. We calculate some bound state energies and transition frequencies which can be studied in the experiment.

hep-ph↗
arXiv2019

Nonrelativistic energies and predissociation widths of quasibound states in the Li$dμ$ molecular ions

Muonic molecular ions $^6$Li$^{3+}dμ$ and $^7$Li$^{3+}dμ$ are studied numerically. Using the complex coordinate rotation method we found six rotational states (three for each isotope), which are resonant states with the life-time of an order of picoseconds. These molecular systems may be of interest for studying low-energy fusion reactions. A key quantity, $|Ψ(0)|^2$, the wave function squared at the coalescence point of the nuclei is calculated for $S$ states for both isotopes with a precision better than 3\%.

physics.atom-ph↗
arXiv2017

The correction of hadronic nucleus polarizability to hyperfine structure of light muonic atoms

The calculation of hadronic polarizability contribution of the nucleus to hyperfine structure of muonic hydrogen and helium is carried out within the unitary isobar model and experimental data on the polarized structure functions of deep inelastic lepton-proton and lepton-deuteron scattering. The calculation of virtual absorption cross sections of transversely and longitudinally polarized photons by nucleons in the resonance region is performed in the framework of the program MAID.

hep-ph↗