Heavy Quark Transport is Non-Gaussian Beyond Leading Log

TL;DR

This paper demonstrates that heavy quark transport at weak coupling exhibits non-Gaussian behavior with asymmetric exponential tails, affecting equilibration in quark-gluon plasmas.

Contribution

It computes the leading-order momentum transfer kernel showing non-Gaussian features beyond leading logarithm in weakly coupled plasmas.

Findings

Momentum transfer distribution has asymmetric exponential tails.

Non-Gaussian features are present at weak coupling, similar to strongly coupled plasmas.

These features are likely universal in quark-gluon plasma dynamics.

Abstract

We find that heavy quark transport beyond leading logarithm at weak coupling is intrinsically non-Gaussian: the longitudinal momentum transfer distribution has asymmetric exponential tails that are crucial for equilibration dynamics. We show this by computing the leading-order momentum transfer kernel for relativistic heavy quarks in weakly coupled non-Abelian plasmas, matching perturbative momentum transfer on the thermal scale to hard-thermal-loop-resummed soft physics. This is the same structure previously found in strongly coupled holographic plasmas, showing that it is not peculiar to weak or strong coupling, conformality, or supersymmetry. We therefore expect that this is a robust feature that physical quark-gluon plasma should also exhibit.