Deep inelastic scattering and the WSS model : a study of holographic pomeron exchange

Abstract

This thesis presents a comparison between a holographic model of the Pomeron in the Witten-Sakai-Sugimoto (WSS) framework and experimental data from the HERA experiment on deep inelastic scattering (DIS). The WSS model, a top-down holographic QCD dual, is utilized to describe the soft Pomeron as an exchange of glueball states. The primary focus of this work is the application of this holographic description to predict the structure functions F1 and F2, which characterize the DIS process at small Bjorken x. The theoretical framework builds on Regge theory and the concept of Reggeon exchange, using the Pomeron trajectory to explain the energy dependence of the cross sections. In this context, we derive the Pomeron-proton vertex, Pomeron propagator, and their coupling photons, utilizing the tensor glueball as the leading state on the Pomeron trajectory. A key result is the derivation of the structure functions in terms of holographic parameters, which are then compared to experimental data from HERA, demonstrating a good qualitative agreement in the regime of small x and low virtuality Q^2. This work provides further insight into the use of holographic models for describing high-energy QCD processes.