The Investigation of Bose Excitations in Quark-Gluon Plasma in Lightcone Gauge

Abstract

We investigate collective excitations in quark‐gluon plasma at high temperatures. Ultrarelativistic plasmas are of importance in cosmology, astrophysics, and high energy nucleus‐nucleus collisions. One of the fundamental properties of a thermal field theory at finite temperatures is the collective excitations, which are characterized by dispersion law ω(p) giving their energy as a function of their momenta p. Collective modes appear mathematically as poles of propagators with well‐defined quantum numbers in the complex plane of the energy: the real part of the pole gives the dispersion law, while the imaginary part gives the damping rate. In this paper, Bose excitations in quark‐gluon plasma are investigated in the lightcone gauge. In order to remove non‐physical singularities, which appear in non‐covariant gauges in non‐abelian gauge field theories, we used the Mandelstam‐Leibbrandt prescription. Gluon self‐energy in the one‐loop approximation is calculated using standard Thermal QCD diagram technique. Bose excitation spectrum is found in the high‐temperature limit and the dispersion equation is shown to be gauge invariant.