Jet quenching and broadening: the transport coefficient $\hat{q}$ in an anisotropic plasma

TL;DR

This paper investigates how the jet quenching parameter $$ varies in an anisotropic quark-gluon plasma, finding it likely increases with anisotropy and discussing implications for high-energy nuclear collisions.

Contribution

It provides the first explicit estimate of $$ in an anisotropic plasma using leading-logarithmic approximation, highlighting the impact of anisotropy on jet quenching.

Findings

$$ increases with plasma anisotropy.

Presence of plasma instability.

Implications for saturation scale $Q_s$ in $A-A$ collisions.

Abstract

The jet quenching parameter $\hat{q}$ is analyzed for a quark jet propagating in an anisotropic plasma. The momentum anisotropy is calculated at high temperature of the underlying quark-gluon plasma. $\hat{q}$ is explicitly estimated in leading-logarithmic approximation by the broadening of the massless quark interacting via gluon exchange. A plasma instability is present. Strong indications are found that $\hat{q}$ is increasing with increasing anisotropy. Possible implications for the saturation scale $Q_s$ in $A-A$ collisions are pointed out.