Calculating the Jet Transport Coefficient $\hat{q}$ in Lattice Gauge Theory

TL;DR

This paper develops a lattice gauge theory method to compute the jet transport coefficient  in a thermal medium, linking perturbative scattering processes with non-perturbative operator evaluations.

Contribution

It introduces a novel approach combining higher twist formalism and lattice gauge theory to calculate  from first principles.

Findings

Leading order transverse momentum broadening calculated

Operator product expansion of  performed and related to local operators

 evaluated in quenched SU(2) lattice gauge theory

Abstract

The formalism of jet modification in the higher twist approach is modified to describe a hard parton propagating through a hot thermalized medium. The leading order contribution to the transverse momentum broadening of a high energy (near on-shell) quark in a thermal medium is calculated. This involves a factorization of the perturbative process of scattering of the quark from the non-perturbative transport coefficient. An operator product expansion of the non-perturbative operator product which represents $\hat{q}$ is carried out and related via dispersion relations to the expectation of local operators. These local operators are then evaluated in quenched SU(2) lattice gauge theory.