Glasma Evolution and Bose-Einstein Condensation with Elastic and Inelastic Collisions

TL;DR

This study examines how inelastic collisions influence the kinetic evolution of overpopulated gluon systems, showing they accelerate Bose-Einstein Condensation by rapidly filling infrared modes and promoting thermalization.

Contribution

It derives the inelastic collision kernel using the Gunion-Bertsch formula and demonstrates its impact on gluon system evolution, highlighting the faster onset of Bose-Einstein Condensation.

Findings

Inelastic collisions reduce total particle number.

Infrared modes fill up rapidly due to inelastic processes.

Bose-Einstein Condensation occurs faster with inelastic collisions.

Abstract

In this paper we investigate the role of inelastic collisions in the kinetic evolution of a highly overpopulated gluon system starting from Glasma-type initial condition. Using the Gunion-Bertsch formula we derive the inelastic collision kernel under the collinear and small angle approximations. With both numerics and analytic analysis, we show that the inelastic process has two effects: globally changing (mostly reducing) the total particle number, while locally at small momentum regime always filling up the infrared modes extremely quickly. This latter effect is found to significantly speed up the emergence of a local thermal distribution in the infrared regime with vanishing local "chemical potential" and thus catalyze the onset of dynamical Bose-Einstein Condensation to occur faster (as compared with the purely elastic case) in the overpopulated Glasma.