Hot and Dense QCD Shear Viscosity at (almost) NLO

Abstract

The next-to-leading order weak-coupling shear viscosity of QCD was computed 6 years ago. However, these results have never been applied at finite baryon chemical potential $\mu$, even though 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 next-to-leading order shear viscosity calculations to finite $\mu$, and we show that, while the convergence of the weak-coupling expansion is questionable for achievable plasmas, it is somewhat better at $\mu > T$ than at $\mu=0$.