Equilibrium and equilibration in a gluon plasma with improved matrix elements

TL;DR

This paper investigates how using exact matrix elements instead of the Gunion-Bertsch approximation affects the understanding of equilibrium and thermalization in a gluon plasma created in heavy ion collisions.

Contribution

It introduces a more accurate calculation of radiative process cross sections and discusses their impact on gluon plasma equilibration.

Findings

Exact matrix element cross sections are significantly smaller than Gunion-Bertsch estimates.

Radiative processes may have a different role in thermalization than previously thought.

Implications for modeling early-stage quark-gluon plasma dynamics.

Abstract

The hot and dense matter created in the early stage of a relativistic heavy ion collision is composed mainly of gluons. Radiative processes can play an important role for the thermalization of such partonic systems. The simplest parton number changing processes are commonly described by the Gunion-Bertsch formula. We show that the cross section from the exact matrix element for the lowest order radiative process could be significantly smaller than that based on the Gunion-Bertsch formula. In light of this, we discuss the role of radiative processes on the equilibrium and equilibration of a gluon plasma.