Holographic Vector Dominance for the Nucleon

TL;DR

This paper develops a two-parameter holographic model for nucleon electromagnetic form factors, fitting experimental data well at low momentum transfer and highlighting the significance of an infinite tower of vector mesons.

Contribution

It introduces a simplified two-parameter formula derived from holographic QCD that effectively models nucleon form factors, emphasizing the role of an infinite tower of vector mesons.

Findings

The model fits experimental data with $ ext{chi}^2$/dof $ extless 2$ for $Q^2 extless 0.5$ GeV$^2$.

The infinite tower of vector mesons is crucial for accurately describing the nucleon structure.

The results suggest a reevaluation of the nucleon's core structure in light of the infinite-tower contributions.

Abstract

We derive a two-parameter formula for the electromagnetic form factors of the nucleon described as an instanton by "integrating out" all KK modes other than the lowest mesons from the infinite-tower of vector mesons in holographic QCD while preserving hidden local symmetry for the resultant vector fields. With only two parameters, the proton Sachs form factors can be fit surprisingly well to the available experimental data for momentum transfers $Q^2\lsim 0.5$ GeV$^2$ with $\chi^2$/dof $\lsim 2$, indicating the importance of an infinite tower in the soliton structure of the nucleon. The prediction of the Sakai-Sugimoto holographic dual model is checked against the fit values that we interpret as representing Nature. The nature of the "core" in the nucleon structure is reassessed in light of the results obtained with the infinite-tower structure.