QCD corrections to the electroweak sphaleron rate

TL;DR

This paper refines the calculation of the electroweak sphaleron rate at high temperatures by including QCD corrections, specifically quark scattering via strong interactions, which slightly reduces the conductivity and sphaleron rate estimates.

Contribution

It introduces leading-log order QCD corrections to the electroweak sphaleron rate calculation, previously considering only electroweak interactions.

Findings

Quark scattering via strong interactions reduces the conductivity by up to 15%.

Total conductivity decreases by up to 6%.

The sphaleron rate estimates are accordingly refined.

Abstract

The electroweak sphaleron rate in the high temperature phase of the Standard Model is inversely proportional to the weak-isospin conductivity. So far, only electroweak interactions were included in its computation. Here we take into account quark scattering through strong interactions at leading-log order. These reduce the quark contribution to the conductivity by up to 15 %, and the total conductivity by up to 6 %.