String-Gauge Dual Description of Deep Inelastic Scattering at Small-$x$

TL;DR

This paper applies the AdS/CFT correspondence to model deep inelastic scattering at small-x, successfully fitting HERA data using the BPST kernel and a simple proton wave function approximation, with implications for other diffractive processes.

Contribution

It formulates a holographic description of small-x DIS using the BPST kernel and demonstrates its effectiveness in fitting experimental data across a range of Q^2 values.

Findings

BPST kernel provides a good fit to HERA data at small-x

The model extends from large to small Q^2 with a simple IR cutoff

Implications for other diffractive processes like Higgs production

Abstract

The AdS/CFT correspondence in principle gives a new approach to deep inelastic scattering as formulated by Polchinski and Strassler. Subsequently Brower, Polchinski, Strassler and Tan (BPST) computed the strong coupling kernel for the vacuum (or Pomeron) contribution to total cross sections. By identifying deep inelastic scattering with virtual photon total cross section, this allows a self consistent description at small-$x$ where the dominant contribution is the vacuum exchange process. Here we formulate this contribution and compare it with HERA small-$x$ DIS scattering data. We find that the BPST kernel along with a very simple local approximation to the proton and current "wave functions" gives a remarkably good fit not only at large $Q^2$ dominated by conformal symmetry but also extends to small $Q^2$, supplemented by a hard-wall cut-off of the AdS in the IR. We suggest that this is a useful phenomenological parametrization with implications for other diffractive processes, such as double diffractive Higgs production.