Comparing energy loss and $p_{\perp}$-broadening in perturbative QCD with strong coupling $\mathcal{N}=4$ SYM theory

TL;DR

This paper compares energy loss and transverse momentum broadening in perturbative QCD and strongly coupled $ ext{N}=4$ SYM theory, revealing similar parametric forms for energy loss and establishing correspondences in broadening mechanisms.

Contribution

It provides a detailed comparison between perturbative QCD and SYM theory for medium-induced energy loss and $p_{ot}$-broadening, highlighting their similarities and differences.

Findings

Identical parametric forms for energy loss in QCD and SYM theory.

Simple correspondences between $p_{ot}$-broadening in QCD and SYM.

Different dominant mechanisms for $p_{ot}$-broadening: radiation vs. multiple scattering.

Abstract

We compare medium induced energy loss and $p_{\perp}$-broadening in perturbative QCD with that of the trailing string picture of SYM theory. We consider finite and infinite extent matter as well as relativistic heavy quarks which correspond to those being produced in the medium or external to it. When expressed in terms of the appropriate saturation momentum, we find identical parametric forms for energy loss in perturbative QCD and SYM theory. We find simple correspondences between $p_{\perp}$-broadening in QCD and in SYM theory although $p_{\perp}$-broadening is radiation dominated in SYM theory and multiple scattering dominated in perturbative QCD.