Momentum transport of chiral modes in a thermal QCD medium

Abstract

We have investigated the effect of a weak magnetic field on momentum transport in a thermal QCD medium at finite quark chemical potential using a semiclassical kinetic theory. In the presence of a magnetic field, the momentum transport coefficients acquire a tensor structure, reflected by the five shear $({\eta }_0,{\eta }_1,{\eta }_2,{\eta }_3$ and ${\eta }_4)$ and two bulk viscous components $({\zeta }_0$ and ${\zeta }_1)$. The weak magnetic field removes the degeneracy in the effective mass of flavours, leading to different masses for the left-handed (L) and right-handed (R) chiral modes of quarks. The coefficients, ${\eta }_0,{\eta }_1$ and ${\eta }_3$ decrease with magnetic field in L mode and increase in $\mathrm{R}$ mode, whereas, ${\eta }_2$ and ${\eta }_4$ increase in both L and $\mathrm{R}$ mode. The bulk viscous coefficients, ${\zeta }_0$ and ${\zeta }_1$ increase with magnetic field for both L and R mode. The shear and bulk viscous coefficients positively amplify with baryon asymmetry.