Are gluon showers inside a quark-gluon plasma strongly coupled? a theorist's test

Abstract

We study whether in-medium showers of high-energy gluons can be treated as a sequence of individual splitting processes $g\to gg$, 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 ${\alpha }_{\mathrm{s}}(\mu )$ 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 ${\hat{q}}_{\mathrm{eff}}$ of the jet-quenching parameter $\hat{q}$.

Comments: 6 pages, 3 figures. Main change for v3: minor clarifications added