Gauge Invariance of Nonlinear Landau Damping Rate of Bose Excitations in Quark-Gluon Plasma

TL;DR

This paper proves the gauge invariance of the nonlinear Landau damping rate of longitudinal plasma excitations in quark-gluon plasma using semiclassical equations and Ward identities, connecting it with existing damping rate frameworks.

Contribution

It demonstrates the gauge invariance of the nonlinear Landau damping rate in QGP and analyzes the physical mechanisms of plasmon scattering, linking it to hard thermal loop results.

Findings

Gauge-dependent part of damping rate vanishes on mass-shell.

Nonlinear damping rate is gauge invariant.

Connection established with damping rates from thermal loop approximations.

Abstract

On the basis of the approximate dynamical equations describing the behavior of quark-gluon plasma (QGP) in the semiclassical limit and Yang-Mills equation, the kinetic equation for longitudinal waves (plasmons) is obtained. With the Ward identities the gauge invariance of obtained nonlinear Landau damping rate is proved. The physical mechanisms defining nonlinear scattering of a plasmon by QGP particles are analyzed. The problem on a connection of nonlinear Landau damping rate of longitudinal oscillations with damping rate, obtained in the framework of hard thermal loops approximation, is considered. It is shown that the gauge-dependent part of nonlinear Landau damping rate for the plasmons with zero momentum vanishes on mass-shell.