Quark and gluon GPDs at finite skewness from strings in holographic QCD: evolved and compared to experiment

TL;DR

This paper develops a holographic QCD framework to construct and evolve Generalized Parton Distributions (GPDs) at finite skewness, successfully comparing theoretical predictions with experimental data for meson electroproduction.

Contribution

It introduces a novel holographic QCD approach to derive and evolve GPDs at finite skewness, bridging non-perturbative modeling with experimental observations.

Findings

Evolved GPDs match experimental meson electroproduction data

Holographic amplitudes effectively extract conformal moments of GPDs

Non-perturbative contributions are significant in the analysis

Abstract

We present a framework for constructing Generalized Parton Distributions (GPDs) using holographic QCD in the large $N_c$ limit, with a focus on low-x and finite skewness. Our approach utilizes holographic amplitudes for exclusive electroproduction processes to extract the spin-j conformal (Gegenbauer) moments of GPDs, which are then evolved to higher resolution scales using QCD evolution equations. Our evolved GPDs (reconstructed from their evolved conformal moments) are applied to analyze the electroproduction of $\rho^{0,+}$ and $\phi$ mesons, and we account for non-perturbative contributions in the $s+u$ - channel using holographic QCD. The results compare well with the existing experimental data. Our GPDs provide detailed information about partonic distributions and are useful for future experimental studies and global data analyses.