The hadron spectra and pion form factor in dynamical holographic QCD model with anomalous 5D mass of scalar field

TL;DR

This paper enhances a dynamical holographic QCD model by incorporating an anomalous 5D mass for the scalar field, enabling simultaneous accurate description of light-flavor hadron spectra and pion form factor, especially for ground and lower states.

Contribution

It introduces an anomalous 5D mass correction to the scalar field in the holographic QCD model, improving the fit to hadron spectra and pion form factor data.

Findings

Improved agreement of scalar, pseudo scalar, and axial vector meson spectra with experimental data.

Enhanced modeling of the pion form factor and hadron spectra simultaneously.

Vector meson spectra remain insensitive to the scalar field mass correction.

Abstract

The simplest version of the dynamical holographic QCD model is described by adding the KKSS model action on a dilaton-graviton coupled background, in which the AdS$_5$ metric is deformed by the gluon condensation and further deformed by the chiral condensation. In this framework, both the chiral symmetry breaking and linear confinement can be realized, the light-flavor hadron spectra and the pion form factor were investigated but it was difficult to reconcile the light-flavor hadron spectra and pion form factor. By considering the anomalous 5-dimension mass correction of the scalar field from QCD running coupling, it is found that the light flavor hadron spectra and pion form factor can be described well simultaneously, especially the ground state and lower excitation states of scalar, pseudo scalar and axial vector meson spectra are improved, but the vector meson spectra is not sensitive to the anomalous 5-dimension mass correction of the scalar field.