Extended soft wall model with background related to features of QCD thermodynamics

TL;DR

This paper extends the soft wall model to incorporate features of QCD thermodynamics, including meson trajectories and phase transitions, aligning model predictions with experimental observations in heavy-ion collisions.

Contribution

The authors develop an extended soft wall model that simultaneously captures meson spectra and various QCD thermodynamic transitions, providing a more comprehensive holographic description.

Findings

Vector meson masses remain stable below T_c, consistent with experimental data.

The model reproduces linear Regge trajectories at zero temperature.

Thermodynamic behaviors match different QCD phase transition scenarios.

Abstract

The soft wall model is extended to accommodate at the same time (i) approximately linear $\rho$ meson Regge trajectories at zero temperature $T$, (ii) various options for the thermodynamics with reference to QCD (cross over or second-order transition or first-order transition at $T_c$), and (iii) the appearance of vector meson states at $T \leq T_c$. While the vector meson masses display some modest model dependence very near to $T_c$, they stay below $T_c$ to good accuracy independent of the temperature, that is nearly as at $T=0$, thus being very consistent with the thermo-statistical models widely employed in analyses of the hadron yields in relativistic heavy-ion collisions in a region where baryon densitiy effects can be neglected and the vacuum hadron masses are used.