Deep inelastic scattering off a N=4 SYM plasma at strong coupling

TL;DR

This paper uses AdS/CFT correspondence to analyze deep inelastic scattering in a strongly coupled N=4 SYM plasma, revealing a transition from weak to complete absorption at a critical energy related to the plasma's temperature and Bjorken x.

Contribution

It provides a novel calculation of structure functions and saturation momentum in a strongly coupled plasma using holography, connecting high-energy scattering to partonic saturation.

Findings

Identifies a sharp transition in scattering behavior at a critical energy.

Derives the saturation momentum as Q_s = T/x.

Suggests a partonic picture with occupation numbers of order one.

Abstract

By using the AdS/CFT correspondence we study the deep inelastic scattering of an R-current off a N=4 supersymmetric Yang-Mills (SYM) plasma at finite temperature and strong coupling. Within the supergravity approximation valid when the number of colors is large, we compute the structure functions by solving Maxwell equations in the space-time geometry of the AdS_5 black three-brane. We find a rather sharp transition between a low energy regime where the scattering is weak and quasi-elastic, and a high-energy regime where the current is completely absorbed. The critical energy for this transition determines the plasma saturation momentum in terms of its temperature T and the Bjorken x variable: Q_s=T/x. These results suggest a partonic picture for the plasma where all the partons have transverse momenta below the saturation momentum and occupation numbers of order one.