High-energy $e^+e^-$ photoproduction cross section close to the end of spectrum

TL;DR

This paper investigates the electron-positron pair production cross section by high-energy photons in strong Coulomb fields near the spectrum's end, revealing significant deviations from previous approximations and including bremsstrahlung results.

Contribution

It provides new calculations of pair production cross sections near the spectrum's end, accounting for Coulomb corrections beyond the Born approximation and including non-ultrarelativistic electron bremsstrahlung.

Findings

Cross section differs significantly from Born approximation near spectrum end.

Coulomb corrections are essential for accurate cross section calculations.

Bremsstrahlung cross section for non-ultrarelativistic electrons is derived.

Abstract

We consider the cross section of electron-positron pair production by a high-energy photon in a strong Coulomb field close to the end of electron or positron spectrum. We show that the cross section essentially differs from the result obtained in the Born approximation as well as form the result which takes into account the Coulomb corrections under assumption that both electron and positron are ultrarelativistic. The cross section of bremsstrahlung in a strong Coulomb field by a high-energy electron is also obtained in the region where the final electron is not ultrarelativistic.