Chiral transition and meson melting within improved holographic soft wall models

TL;DR

This paper extends improved holographic soft wall models to finite temperature to study chiral transition and meson melting in two-flavor QCD, providing insights into the temperature-dependent behavior of mesons and chiral symmetry restoration.

Contribution

It introduces a finite-temperature extension of improved holographic soft wall models to analyze chiral transition and meson melting in two-flavor QCD.

Findings

Chiral transition is second order in the chiral limit and a crossover with physical quark masses.

Mesons melt at temperatures between 90 and 110 MeV.

Chiral transition occurs around 129 MeV.

Abstract

We describe the chiral transition for the quark condensate and the melting of scalar and vector mesons in two-flavor holographic QCD. This is done by extending the improved holographic soft wall models proposed in [1] to finite temperature, by means of introducing an asymptotically AdS black brane. We find that the chiral transition is second order in the chiral limit and a crossover for physical quark masses, as expected in two-flavor QCD. We investigate the melting of vector and scalar mesons in the deconfined plasma through the calculation of hadronic spectral functions. Fixing the model parameters by the meson spectrum at zero temperature, we find that the mesons melt at temperatures between $90$ and $110$ MeV and the chiral transition occurs around $129$ MeV. We also provide a prediction for the hydrodynamic diffusion constant associated with a flavor current in the deconfined plasma.