Charge asymmetry in the differential cross section of high-energy bremsstrahlung in the field of a heavy atom

TL;DR

This paper investigates charge asymmetry in high-energy bremsstrahlung differential cross sections in the field of a heavy atom, using quasiclassical approximation and exact atomic field considerations, highlighting differences for electrons and muons.

Contribution

It introduces a detailed analysis of charge asymmetry in bremsstrahlung, accounting for first quasiclassical corrections and atomic field effects, with specific focus on electrons and muons.

Findings

Charge asymmetry arises from first quasiclassical correction.

Nuclear size effects are negligible for electrons but significant for muons.

Asymmetry depends on azimuthal angle and particle polarization.

Abstract

The distinction between the charged particle and antiparticle differential cross sections of high-energy bremsstrahlung in the electric field of a heavy atom is investigated. The consideration is based on the quasiclassical approximation to the wave functions in the external field. The charge asymmetry (the ratio of the antisymmetric and symmetric parts of the differential cross section) arises due to the account for the first quasiclassical correction to the differential cross section. All evaluations are performed with the exact account of the atomic field. We consider in detail the charge asymmetry for electrons and muons. For electrons, the nuclear size effect is not important while for muons this effect should be taken into account. For the longitudinal polarization of the initial charged particle, the account for the first quasiclassical correction to the differential cross section leads to the asymmetry in the cross section with respect to the replacement $\varphi\rightarrow-\varphi$, where $\varphi$ is the azimuth angle between the photon momentum and the momentum of the final charged particle.