Bulk viscous corrections to screening and damping in QCD at high temperatures

TL;DR

This paper investigates how bulk viscous effects alter the screening and damping properties of gluons in high-temperature QCD, impacting quarkonium states and soft gluon dynamics near critical points.

Contribution

It calculates bulk viscous corrections to hard thermal loops in QCD, linking these effects to critical phenomena and their influence on gluon propagators.

Findings

Bulk viscous corrections modify gluon screening and damping masses.

These modifications are sensitive to bulk pressure and critical scaling.

Implications for quarkonium properties and soft gluon dynamics near critical points.

Abstract

Non-equilibrium corrections to the distribution functions of quarks and gluons in a hot and dense QCD medium modify the "hard thermal loops" (HTL). The HTLs determine the retarded, advanced, and symmetric (time-ordered) propagators for gluons with soft momenta as well as the Debye screening and Landau damping mass scales. We compute such corrections to a thermal as well as to a non-thermal fixed point.The screening and damping mass scales are sensitive to the bulk pressure and hence to (pseudo-) critical dynamical scaling of the bulk viscosity in the vicinity of a second-order critical point. This could be reflected in the properties of quarkonium bound states in the deconfined phase and in the dynamics of soft gluon fields.