Improved Bethe-Heitler formula

Abstract

The bremsstrahlung cross section of electron in the atomic electric field is re-derived using the time ordered perturbative theory. The results are compared with the Bethe-Heitler formula. We indicate that both the TOPT-description and a soft version for the bremsstrahlung process predict a strong screening parameter-dependent cross section, which is missed by previous bremsstrahlung theory.

Comments: 22 pages, 6 figures. Paper has been covered by arXiv:hep-ph/1909.03053