Chiral Phase Transition and Meson Melting from AdS/QCD

TL;DR

This paper models the behavior of mesons under finite temperature and chemical potential using AdS/QCD, revealing details about chiral phase transitions and meson melting that align with lattice results.

Contribution

It introduces a quartic scalar potential in a soft-wall AdS/QCD model to accurately describe chiral symmetry breaking and meson spectra.

Findings

Chiral transition is second-order at zero quark mass and a crossover at physical mass.

Transition temperatures are consistent with lattice QCD results.

Meson melting occurs before the chiral phase transition, maintaining vector-axial vector mass splitting.

Abstract

We investigate the in-medium behavior of mesons at finite temperature and baryon chemical potential within a soft-wall model of AdS/QCD. We use a quartic scalar potential to obtain the correct form of chiral symmetry breaking. At zero quark mass the chiral phase transition is second-order, becoming a crossover at physical quark mass. At zero baryon chemical potential, we find a chiral transition temperature of 155 MeV in the chiral limit and a pseudo-transition temperature of 151 MeV at physical quark mass, consistent with lattice results. In the low-temperature limit, the second-order transition occurs at a baryon chemical potential of 566 MeV while the rapid crossover occurs at 559 MeV. A new parameterization of the dilaton profile results in improved meson spectra. Meson melting occurs at a lower temperature and chemical potential than the chiral phase transition, so the vector-axial vector mass splitting remains constant until the bound states melt.