Jet quenching in the glasma phase: medium-induced radiation

TL;DR

This paper investigates how jet partons lose energy through medium-induced soft gluon radiation in the early glasma phase of heavy-ion collisions, highlighting the influence of color domain structures on radiation rates.

Contribution

It introduces a model for medium-induced radiation in the glasma phase considering independent color domains and event averaging, providing new insights into jet quenching mechanisms.

Findings

Radiation rate decreases with smaller color domains.

Interplay of synchrotron-like radiation and destructive interference affects emission.

Model can be extended to more realistic collision backgrounds.

Abstract

Inspired by the recent considerations of parton momentum broadening in the glasma phase, we study the medium-induced soft gluon radiation of jet partons at early times in heavy-ion collisions. The glasma state is assumed to be comprised of independent color domains with homogenous longitudinal fields that vary event by event, and we further complete this model with an event-averaging procedure accounting for the finite correlation length. Using this description, we evaluate the rate of medium-induced radiation from an energetic parton at midrapidity in the glasma phase. We mainly focus on SU(2) color fields for simplicity, also referring to the U(1) case and comparing with the BDMPS-Z rate to gain further insight. Our results show that there is an intricate interplay of the synchrotron-like radiation in a single color domain with the destructive interference between different color domains, after the medium averaging is performed. Thus, we find that the emission rate is sensitive to the matter structure, decreasing for a glasma state populated by smaller color domains, i.e. for a glasma with a larger characteristic saturation scale. Our approach can be applied to more realistic backgrounds, and sets the stage for the modelling of jet evolution in the early stages of heavy-ion collisions.