The Virtual Photon Structure Functions and AdS/QCD Correspondence

TL;DR

This paper investigates the structure functions of virtual photons using gauge/string duality, demonstrating that supergravity approximations are valid at moderate x and large 't Hooft coupling, and confirms the Callan-Gross relation approximately holds.

Contribution

It provides a novel calculation of virtual photon structure functions at large coupling and moderate x using AdS/QCD correspondence, extending previous approaches.

Findings

Supergravity approximation is valid at moderate x.

Calculated structure functions match expected x-behavior.

Callan-Gross relation F_L=0 holds approximately.

Abstract

We study the virtual photon structure functions from gauge/string duality. If the Bjorken variable x is not small, supergravity approximation becomes good in dual string theory. We calculate the virtual photon structure functions at large 't Hooft coupling in a moderate x-region and determine x-behavior of the structure functions. We also show that the Callan-Gross relation F_L=0 is satisfied to a good approximation in gravity calculation.