Charge asymmetry in the spectra of bremsstrahlung and pair production

TL;DR

This paper calculates the first Coulomb correction to bremsstrahlung and pair production spectra, revealing charge asymmetry effects beyond the Born approximation and high-energy limits, using advanced multiloop techniques.

Contribution

It introduces the first Coulomb correction to these spectra, showing they are not related by crossing symmetry and providing detailed asymptotic behaviors.

Findings

Coulomb corrections determine leading charge asymmetry.

Corrections differ from Born approximation and high-energy results.

Results expressed in classical polylogarithms.

Abstract

We calculate the first Coulomb correction to the spectra of two processes: the electron bremsstrahlung and electron-positron photoproduction in the Coulomb field. We show that, in contrast to the results obtained in the Born approximation and in the high-energy limit, the obtained corrections for these two process are not related by the crossing symmetry substitutions. The found corrections determine the leading contribution to the charge asymmetry in these processes. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. The results are presented in terms of classical polylogarithms. We provide both the threshold and the high-energy asymptotics of the obtained expressions and compare them with available results.