The nucleon structure from an AdS/QCD model in the Veneziano limit

TL;DR

This paper uses a holographic VQCD model to calculate various proton properties, including mass spectrum, structure functions, and form factors, showing excellent agreement with experimental and lattice QCD data.

Contribution

It introduces a comprehensive holographic VQCD approach that captures key QCD features and accurately predicts proton properties, advancing the modeling of hadronic physics.

Findings

Proton mass spectrum and wave functions match experimental data.

Proton structure functions are consistent with known results.

Electromagnetic and gravitational form factors agree with lattice QCD and experiments.

Abstract

We employ the VQCD model, a holographic approach that dynamically simulates essential QCD characteristics, including linear mass spectra, confinement, asymptotic freedom, and magnetic charge screening, while incorporating quark flavor effects. Using this model, we first calculate the proton mass spectrum and the wave function, incorporating anomalous dimensions to refine our results. Next, we compute the proton structure functions across a range of Bjorken $x$ values using consistent parameters. Furthermore, we derive the proton electromagnetic form factor by solving the electromagnetic field's motion equation, accounting for background effects, and demonstrate qualitative consistency with results from free electromagnetic fields coupled to fermions. Finally, we calculate the gravitational form factors by introducing an effective graviton mass $m$ arising from chiral symmetry breaking and the proton energy-momentum tensor. Our calculations yield results that are in excellent agreement with experimental data and lattice QCD computations, validating the VQCD model as a robust tool for studying proton properties.