Hot and Dense QCD Shear Viscosity at Leading Log

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 $\mu=0$.