Are Parton Showers in a Quark-Gluon Plasma Strongly Coupled? A Theorist's Test

TL;DR

This paper investigates whether high-energy parton showers in a quark-gluon plasma can be modeled as independent splitting events or if quantum overlap effects are significant, using theoretical calculations including the LPM effect.

Contribution

It provides a leading-order calculation of quantum overlap effects in in-medium parton showers, considering the LPM effect, and introduces a measure independent of the effective jet-quenching parameter.

Findings

Overlap effects can be quantified at leading order in high-energy $\

Quantum overlap effects are significant in the modeling of parton showers in a quark-gluon plasma.

The measure of overlap effects is independent of the effective jet-quenching parameter $\

Abstract

We study whether in-medium showers of high-energy quarks and gluons can be treated as a sequence of individual splitting processes or whether there is significant quantum overlap between where one splitting ends and the next begins. Accounting for the Landau-Pomeranchuk-Migdal (LPM) effect, we calculate such overlap effects to leading order in high-energy $\alpha_s(\mu)$ for the simplest theoretical situation. We investigate a measure of overlap effects that is independent of physics that can be absorbed into an effective value $\hat{q}_{eff}$ of the jet-quenching parameter $\hat{q}$.