Confront Holographic QCD with Regge Trajectories of vectors and axial-vectors

TL;DR

This paper connects holographic QCD models with Regge trajectories of vector and axial-vector mesons, showing how the $AdS_5$ soft-wall model can effectively describe their spectra and chiral symmetry behaviors.

Contribution

It derives the 5D metric structure of the $Dp-Dq$ system and relates it to Regge trajectories, demonstrating the $AdS_5$ soft-wall model's effectiveness in describing meson spectra.

Findings

The $AdS_5$ soft-wall model fits vector meson spectra well.

A small negative $z^4$ correction aids in modeling chiral symmetry restoration.

The constant component of axial-vector meson mass squared is key to chiral symmetry breaking.

Abstract

We derive the general 5-dimension metric structure of the $Dp-Dq$ system in type II superstring theory, and demonstrate the physical meaning of the parameters characterizing the 5-dimension metric structure of the \textit{holographic} QCD model by relating them to the parameters describing Regge trajectories. By matching the spectra of vector mesons $\rho_1$ with deformed $Dp-Dq$ soft-wall model, we find that the spectra of vector mesons $\rho_1$ can be described very well in the soft-wall $D3-Dq$ model, i.e, $AdS_5$ soft-wall model. We then investigate how well the $AdS_5$ soft-wall model can describe the Regge trajectory of axial-vector mesons $a_1$. We find that the constant component of the 5-dimension mass square of axial-vector mesons plays an efficient role to realize the chiral symmetry breaking in the vacuum, and a small negative $z^4$ correction in the 5-dimension mass square is helpful to realize the chiral symmetry restoration in high excitation states.