Hot and Dense QCD Shear Viscosity at Leading Log

TL;DR

This paper extends the calculation of shear viscosity in QCD to finite baryon chemical potential, providing insights relevant for heavy ion collisions and neutron star mergers where baryon density is high.

Contribution

It introduces a leading-log shear viscosity calculation at finite chemical potential, addressing a gap in applying weak-coupling results to dense QCD matter.

Findings

Extension of shear viscosity calculation to finite $mbda$

Better convergence of weak-coupling expansion at high chemical potential

Relevance for heavy ion collisions and neutron star mergers

Abstract

The leading-order weak-coupling shear viscosity of QCD was computed almost 20 years ago, and the extension to next-to-leading order is 4 years old. But these results have never been applied at finite baryon chemical potential $\mu$, despite the fact that intermediate-energy heavy ion collisions and merging neutron stars may explore the Quark-Gluon Plasma in a regime where baryon chemical potentials are large. Here we extend the leading-log shear viscosity calculation to finite $\mu$, and we argue that the convergence of the weak-coupling expansion, while questionable for achievable plasmas, should be better at $\mu > T$ than at $\mu=0$.