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A. I. Milstein

Publications and source records attributed to A. I. Milstein.

At least 19 recordsLinked to original sources
arXiv2026

Near-threshold resonances in $e^+e^-$ annihilation

Near-threshold resonances have been discovered in many hadron pair production processes, resulting in a significant increase in reaction cross sections at low relative velocities of the produced particles. The natural cause of such resonances is the interaction between slow hadrons in the final state. Our review demonstrates that, in virtually all known cases, final-state interactions successfully explain the results of numerous experiments demonstrating a nontrivial energy dependence of cross sections for processes near reaction thresholds. A comprehensive study of near-threshold resonances in various processes can provide new information about the interaction between hadrons at large distances.

hep-ph↗
arXiv2026

Quasiparticles and ion cooling by an electron beam in a strong magnetic field

The frictional force arising from the interaction of ions with a magnetized electron beam in a strong magnetic field is investigated. The problem is reduced to the interaction of quasiparticles, or Larmor circles, with ions. A Hamiltonian describing this interaction is derived. The role of various impact parameters in the process of ion cooling is elucidated. The cases of both positively and negatively charged ions are considered.

physics.plasm-ph↗
arXiv2026

Electron scattering by a magnetic monopole in solid-state experiments

The scheme of experiment for studying electron scattering in the field of a magnetic monopole in two dimensional electron gas is proposed. The differential scattering cross section is obtained in the eikonal approximation. For unpolarized initial electron, the differential cross section coincides with that in the field of an infinitely long solenoid, up to redefinition of a magnetic flux. It is shown that the scattered electron becomes polarized even for unpolarized initial electron. Besides, in an experimental setup similar to the Hall experiment, the spin polarization arises in the direction perpendicular to the electron current.

cond-mat.mes-hall↗
arXiv2026

Charge asymmetry in $e^{+}e^{-}\to B^{(*)}\bar{B}^{(*)}$ processes in the vicinity of $Υ(4S)$

The effects of isotopic invariance violation in the processes $e^{+}e^{-}\to B\bar{B}$, $e^{+}e^{-}\to B^{*}\bar{B}$, and $e^{+}e^{-}\to B^{*}\bar{B}^{*}$ are considered in the energy range between the thresholds of $B^{+}B^{-}$ and $B_{s}^{0}\bar{B}_{s}^{0}$ production. The analysis is based on taking into account the final-state interaction in a six-channel problem. Our approach allowed us to obtain good agreement with recent Belle-II results for the ratio of the $B^{0}\bar{B}^{0}$ and $B^{+}B^{-}$ production cross sections in $e^{+}e^{-}$ annihilation in the vicinity of $Υ(4S)$. It is shown that at higher energies the ratios of the cross sections for pairs of neutral and charged $B^{(*)}$ mesons can differ significantly from unity. A detailed measurement of this effect will provide evidence that the nontrivial energy dependence of the $B^{(*)}\bar{B}^{(*)}$ production cross sections is a consequence of interference of the particle production amplitudes in the multichannel problem.

hep-ph↗
arXiv2026

Relativistic effects in heavy mesons

We discuss the application of a relativistic potential model to the description of the spectrum and radiative transitions in mesons containing at least one heavy quark (b or c). Although the model has a small number of parameters, it is possible to achieve qualitative agreement with all available experimental data, including those that could not be explained by all previous methods. This demonstrates the importance of taking relativistic effects into account. A remarkable property of the relativistic potential model is that the predictions for meson masses and partial widths of radiative transitions remain finite in the limit of zero light quark mass.

hep-ph↗
arXiv2025

Charge asymmetry in the process $e^+e^-\to π^+π^-π^0γ$

The charge asymmetry in the process $e^+e^-\to π^+π^-π^0γ$ is studied for photons with energies $ν\ll\sqrt{s}$. The longitudinal polarization of electrons (positrons) is taken into account. The asymmetry arises due to interference of the amplitudes for production of pion states with opposite $C$ parities. The contribution of $a_1^0(1260)$ meson in the intermediate state to the charge asymmetry is discussed. This contribution is not the leading one, however it is not negligible. It is shown that the charge asymmetry can reach several tens of percent.

hep-ph↗
arXiv2025

Finite length of the solenoid and the Aharonov-Bohm effect

The scattering of a nonrelativistic electron on a narrow solenoid of finite length is considered. In this case, the magnetic field outside the solenoid is not zero. Using the eikonal approximation, the differential and total cross sections of the process are found. It is shown that the total cross section is finite, in contrast to the case of scattering on an infinitely long solenoid (Aharonov-Bohm effect). An asymmetry in the scattering cross section is also found, which can be observed in an experiment.

physics.atom-ph↗
arXiv2025

Relativistic effects in $\mbox{M1}$ radiative decays of heavy-light mesons

We discuss the $\mbox{M1}$ radiative transitions $D^*\rightarrow Dγ$, $D_{s}^*\rightarrow D_sγ$, $B^*\rightarrow Bγ$, and $B^*_{s}\rightarrow B_sγ$. A relativistic potential model is proposed. The corresponding Hamiltonian, when expanded to terms of the order of $v^2/c^2$, where $v$ are the quark velocities, coincides with the Breit Hamiltonian. This model allows making predictions for the widths of radiative transitions of mesons with one light quark. Taking into account relativistic effects is especially important for the transitions $D_{s}^{*+}\rightarrow D_s^+γ$ and $D^{*+}\rightarrow D^+γ$, where there is a large compensation in the magnitude of the magnetic moment of these mesons. Our results are consistent with known experimental data.

hep-ph↗
arXiv2025

Phenomenology of $D_{s1}$ mesons radiative transitions

We discuss radiative transitions $D_{s1}\rightarrow D_sγ$ and $D_{s1}\rightarrow D_s^*γ$ of $p$-wave mesons. Since $D_{s1}$ mesons have no a certain $C$-parity, and the masses of quarks in these mesons differ significantly, then due to the spin-orbit interaction each of $p$-wave mesons with the total angular momentum $J=1$ is a superposition of states with the total spin of quarks $S_{tot}=0$ and $S_{tot}=1$. We explain why the partial width of $D_{s1}(2460)\to D_sγ$ radiative transition is significantly larger than the corresponding value for $D_{s1}(2536)\to D_sγ$. We also predict the corresponding partial widths of $B_{s1}$ and $B_{c1}$.

hep-ph↗
arXiv2025

Discrete spectrum of edge states in a two-dimensional topological insulator

The interaction model of two electrons in the edge states of a two-dimensional topological insulator is investigated. Both solutions of the Schrödinger equation and solutions of the Bethe-Salpeter equation at different values of the Fermi energy are considered. It is shown that for the Bethe-Salpeter equation, which takes into account the existence of the Fermi surface, there is a discrete spectrum in the system of two electrons. This phenomenon does not appear in the case of the Schrödinger equation.

cond-mat.mes-hall↗
arXiv2024

Non-stationary Aharonov-Bohm effect

The non-stationary Aharonov-Bohm effect (scattering of electron in the field of a narrow solenoid with alternating current) is considered. Using the eikonal approximation, the wave function of electron, the differential and total scattering cross sections are found. Unlike the case of direct current, the total cross section in the case of alternating current turns out to be finite. An oscillating asymmetry in the differential scattering cross section is discovered. The possibility of experimental observation of the effect is discussed.

physics.atom-ph↗
arXiv2024

Manifestation of $a_1(1260)$ meson in the process $e^+e^-\to π^+π^-π^0$

The charge asymmetry in the process $e^+e^-\to π^+π^-π^0$ is studied taking into account a longitudinal polarization of electrons (positrons). The asymmetry arises due to interference of amplitudes corresponding to production of pions in C-odd and C-even states. It is a manifestation of $a_1(1260)$ meson in the intermediate state. Polarization leads to additional correlations in the differential cross section, which simplifies the experimental study of the process. It is shown that the charge asymmetry can reach several percent.

hep-ph↗
arXiv2024

Non-trivial solution to a simple problem

The problem of finding the frequencies of small longitudinal oscillations of a spring having a finite mass and stiffness, attached at one end to a wall and at the other end to a body of finite mass, is discussed. This problem was repeatedly proposed at Olympiads for schoolchildren, in various lessons on the Internet, and even on tests in mechanics for students of universities. In all the cases known to me, the implied solution was actually wrong. I discuss two cases: (A) a spring lies on a smooth table, (B) a spring is attached to the ceiling. It is shown that the solution to this simply formulated problem is non-trivial.

physics.pop-ph↗
arXiv2024

Production of $D^{(*)}\bar{D}^{(*)}$ near the thresholds in $e^{+}e^{-}$ annihilation

It is shown that the nontrivial energy dependencies of $D\bar{D}$, $D\bar{D}^{*}$, and $D^{*}\bar{D}^{*}$ pair production cross sections in $e^{+}e^{- }$ annihilation are well described within the approach based on account for the final-state interaction of produced particles. This statement is valid for production of charged and neutral particles. Interaction of $D^{(*)}$ and $\bar{D}^{(*)}$ is taken into account using the effective potential method. Its applicability is based on the fact that for near-threshold resonance the characteristic width of peak in the wave function is much larger than the interaction radius. The transition amplitudes between all three channels play an important role in the description of cross sections. These transitions are possible since all channels have the same quantum numbers $J^{PC}=1^{--}$.

hep-ph↗
arXiv2023

Meson production in $J/ψ$ decays and $J/ψ\to N\bar{N}γ$ process

It is shown that an account for the final-state interaction of real or virtual nucleon and antinucleon produced in the processes $J/ψ\to p\bar{p}γ$, $ψ(2S)\to p\bar{p}γ$, $J/ψ\to p\bar{p}ω$, and $J/ψ\to3\left(π^{+}π^{-}\right)γ$ near the threshold of $N\bar{N}$ pair production allows one to obtain self-consistent description of these processes. Predictions of our model are in good agreement with experimental data available. The proposed potential model also reproduces the corresponding partial cross sections of $p\bar{p}$ scattering.

hep-ph↗
arXiv2023

Near-threshold resonance in $e^{+}e^{-}\rightarrowΛ_{c}\barΛ_{c}$ process

We discuss the influence of various contributions of the $Λ_{c}\barΛ_{c}$ potential on the energy dependence of the cross section $e^{+}e^{-}\rightarrowΛ_{c}\barΛ_{c}$ near the threshold. New BESIII experimental data on the cross section and electromagnetic form factors $G_{E}$ and $G_{M}$ are taken into account. Our predictions are in good agreement with experimental data. We predict a bound state of $Λ_{c}\barΛ_{c}$ at energy $\sim 38~\textrm{MeV}$ below the threshold that may manifest itself in anomalous behavior of light meson production cross sections in a given energy region.

hep-ph↗
arXiv2023

Atomic screening and $e^+e^-$ pair photoproduction at low energies

The effect of screening by atomic electrons on the behavior of electron and positron wave functions in the continuous spectrum at small distances is studied. It is shown that these asymptotics are affected not only by the static potential of atomic electrons, but also by the polarization potential, as well as by the exchange interaction, which is essential for nonrelativistic electrons. A simple analytical expression is obtained for the photoproduction cross section of $e^+e^-$ pair in an atomic field near the threshold. The spectrum and angular distribution of the produced particles are considered. It is shown that screening significantly affects the cross section in the near-threshold region.

physics.atom-ph↗