Hard parton dispersion in the quark-gluon plasma, non-perturbatively

TL;DR

This paper investigates the non-perturbative contributions to the dispersion of high-energy partons in quark-gluon plasma, utilizing lattice QCD and effective theory techniques to improve understanding of their infrared behavior.

Contribution

It introduces a method combining lattice EQCD calculations with perturbative matching to accurately determine the classical gluon contributions to parton dispersion in hot QCD.

Findings

Lattice EQCD results agree with perturbative calculations in the UV regime.

Non-perturbative classical gluon effects significantly impact parton dispersion.

A framework for combining lattice and perturbative methods is established.

Abstract

The in-medium dispersion of hard partons, encoded in their so-called asymptotic mass, receives large non-perturbative contributions from classical gluons, i.e. soft gluons with large occupation numbers. Here, we discuss how the analytical properties of thermal amplitudes allow for a non-perturbative determination of the infrared classical contribution through lattice determinations in the dimensionally-reduced effective theory of hot QCD, EQCD. We show how these lattice determinations need to be complemented by perturbative two-loop matching calculations between EQCD and QCD, so that the unphysical (classical) ultraviolet behavior of EQCD is replaced by its proper quantum QCD counterpart. We show how lattice and perturbative EQCD are in good agreement in the UV and present an outlook on the two-loop quantum QCD contribution.