Revisiting transverse momentum broadening in dense QCD media

TL;DR

This paper revisits the calculation of transverse momentum broadening for energetic partons in dense QCD media, providing a simplified formula applicable to jet quenching studies and analyzing model sensitivities.

Contribution

It derives a unified analytic formula for momentum broadening that covers soft and hard scattering regimes and compares non-perturbative models, confirming their negligible impact at collider energies.

Findings

Derived a simple analytic formula for momentum broadening.

Compared HTL and Gyulassy-Wang models, finding minimal differences.

Confirmed the robustness of jet quenching predictions at collider energies.

Abstract

We reconsider the problem of transverse momentum broadening of a highly-energetic parton suffering multiple scatterings in dense colored media, such as the thermal Quark-Gluon plasma or large nuclei. In the framework of Moli\`ere's theory of multiple scattering we re-derive a simple analytic formula, to be used in jet quenching phenomenology, that accounts for both the multiple soft and hard Rutherford scattering regimes. Further, we discuss the sensitivity of momentum broadening to modeling of the non-perturbative infrared sector by presenting a detailed analytic and numerical comparison between the two widely used models in phenomenology: the Hard Thermal Loop and the Gyulassy-Wang potentials. We show that for the relevant values of the parameters the non-universal, model dependent contributions are negligible, at LHC, RHIC and EIC energies thus consolidating the predictive power of jet quenching theory.