Modification of heavy quark energy loss due to shear flow in hot QCD plasma

TL;DR

This paper derives how shear flow in a viscous QCD plasma alters heavy quark energy loss, incorporating non-equilibrium effects and screening, revealing significant impact of shear flow on energy dissipation.

Contribution

It provides a novel derivation of heavy quark energy loss in viscous QCD plasma accounting for shear flow and non-equilibrium effects using kinetic theory and HTL resummation.

Findings

Shear flow significantly modifies heavy quark energy loss.

Infrared divergences are mitigated by HTL screening effects.

Shear flow effects are quantitatively important in QCD plasmas.

Abstract

We present the derivation of heavy quark energy loss in a viscous QCD plasma using kinetic theory. Shear flow changes both boson and fermion distribution functions which eventually modify heavy quark energy loss. Due to presence of non-zero flow gradient in the medium all the bath particles here are out of equilibrium. In these types of plasmas we show that without plasma screening effects heavy quark energy loss suffers similar type of infrared divergence as one encounters in non-viscous plasma. The screening effects are incorporated consistently through Hard Thermal Loop resummation perturbation theory in the small-momentum-transfer region to obtain finite leading order result in $\eta/s$. We also quantify the importance of the result and demonstrate that shear flow has significant effect on the heavy quark energy loss.