Deeply Virtual Compton Scattering from Gauge/Gravity Duality

TL;DR

This paper employs gauge/gravity duality to analyze deeply virtual Compton scattering at high energies, modeling the pomeron exchange via AdS space and comparing results with experimental data from HERA.

Contribution

It introduces a strong coupling model of the pomeron as a graviton Regge trajectory in AdS space, incorporating confinement effects and saturation phenomena, and compares with experimental data.

Findings

Model agrees with HERA data over a large kinematic range.

The AdS black disk model explains high-energy behavior inside saturation.

Pomeron exchange described by conformal Regge theory at various couplings.

Abstract

We use gauge/gravity duality to study deeply virtual Compton scattering (DVCS) in the limit of high center of mass energy at fixed momentum transfer, corresponding to the limit of low Bjorken x, where the process is dominated by the exchange of the pomeron. Using conformal Regge theory we review the form of the amplitude for pomeron exchange, both at strong and weak 't Hooft coupling. At strong coupling, the pomeron is described as the graviton Regge trajectory in AdS space, with a hard wall to mimic confinement effects. This model agrees with HERA data in a large kinematical range. The behavior of the DVCS cross section for very high energies, inside saturation, can be explained by a simple AdS black disk model. In a restricted kinematical window, this model agrees with HERA data as well.