0th Order Heavy Quark Photon Bremsstrahlung

TL;DR

This paper calculates the distribution of massive photon (gluon) radiation from heavy quarks at zeroth order, examining interference effects and the impact of approximations on energy loss, with implications for heavy quark energy loss in QCD.

Contribution

It provides a detailed calculation of heavy quark photon (gluon) bremsstrahlung including interference effects and assesses the impact of common approximations on energy loss estimates.

Findings

Approximation of 1-x as 1 significantly affects energy loss magnitude.

Including radiation from the away-side jet restores gauge invariance and fills the dead cone.

Ter-Mikayelian effect reduces vacuum energy loss by 10-40% for 5-25 GeV heavy quarks.

Abstract

We calculate the 0th order in opacity number distribution of massive photons (gluons) for heavy quark production radiation including interference from the away-side jet. While consistent with the soft photon (gluon) approximation, we find that approximating 1-x with 1, as done in previous calculations, strongly affects the magnitude of energy loss. Restoring gauge invariance by including the radiation associated with the away-side jet fills in the "dead cone," but is a relatively small effect. The Ter-Mikayelian reduction from vacuum energy loss is 10-40% for 5-25 GeV charm and bottom quarks.