Jets in QCD media: from color coherence to decoherence

TL;DR

This paper studies how soft gluon radiation from a quark-antiquark pair in a dense medium becomes decoherent due to multiple scatterings, affecting jet behavior in heavy-ion collisions.

Contribution

It introduces a detailed analysis of color decoherence of a quark-antiquark antenna in a dense medium, highlighting the transition to independent radiation in opaque conditions.

Findings

Decoherence increases with medium density.

Complete decoherence occurs in an opaque medium.

Antennas radiate independently in the fully opaque limit.

Abstract

We investigate soft gluon radiation off a quark-antiquark antenna in both color singlet and octet configurations traversing a dense medium. We demonstrate that, in both cases, multiple scatterings lead to a gradual decoherence of the antenna radiation as a function of the medium density. In particular, in the limit of an completely opaque medium, total decoherence is obtained, i.e., the quark and the antiquark radiate as independent emitters in vacuum, thus losing memory of their origin. We comment on possible implications on intrajet observables in heavy-ion collisions.