Parton picture for the strongly coupled SYM plasma

TL;DR

This paper uses the AdS/CFT correspondence to analyze the strongly coupled N=4 SYM plasma, revealing a parton cascade process and identifying a saturation momentum scale that governs jet quenching phenomena.

Contribution

It introduces a parton picture for the strongly coupled plasma and identifies the saturation momentum scale Q_s as key to understanding jet interactions.

Findings

Parton cascade down to small x and transverse momenta.

Saturation momentum Q_s controls jet energy loss.

Cascade process suggests a universal behavior in strongly coupled plasma.

Abstract

Deep inelastic scattering off the strongly coupled N=4 supersymmetric Yang-Mills plasma at finite temperature can be computed within the AdS/CFT correspondence, with results which are suggestive of a parton picture for the plasma. Via successive branchings, essentially all partons cascade down to very small values of the longitudinal momentum fraction x and to transverse momenta smaller than the saturation momentum Q_s\sim T/x. This scale Q_s controls the plasma interactions with a hard probe, in particular, the jet energy loss and its transverse momentum broadening.