Equations, chromopermittivity and instabilities of the quark-gluon medium

TL;DR

This paper investigates the properties of the quark-gluon medium at high energies, introducing chromopermittivity, analyzing instabilities, and predicting Cherenkov gluon emission, which varies with energy and differs from lower-energy phenomena.

Contribution

It introduces the concept of chromopermittivity in the quark-gluon medium and analyzes its implications for instabilities and Cherenkov gluon emission at TeV energies.

Findings

Chromopermittivity exceeds 1 at TeV energies.

The medium exhibits instabilities and Cherenkov gluon emission.

Differences in gluon distributions between LHC and RHIC energies.

Abstract

The quark-gluon medium described by QCD equations is considered at high energies. Within the assumptions of the linear response theory the chromopermittivity of the medium is introduced and it is argued that it exceeds 1 at TeV energies. The dispersion equations show that the proper modes of the medium reveal instability and the parton currents traversing it induce the emission of Cherenkov gluons. Their distributions at LHC can differ from those typical for lower energies of RHIC because they are determined by the high energy dependence of the chromopermittivity while the latter ones arise due to collective resonance excitations. The distinction between Cherenkov gluons and Mach waves is discussed.