Testing the hadronic spectrum in the strange sector

TL;DR

This paper investigates the hadronic spectrum in the strange sector, incorporating additional predicted states to improve the hadron resonance gas model's agreement with lattice QCD data, and introduces a method to determine the freeze-out temperature from experimental data.

Contribution

It proposes a first-principles method to extract the freeze-out temperature for charged kaons, providing a lower bound at high collision energies.

Findings

Including predicted states slightly lowers the freezeout temperature.

The method yields a lower bound of approximately 145 MeV for RHIC energies.

Adding states improves the hadron resonance gas model's accuracy.

Abstract

Heavier resonances are continually being added to the hadronic spectrum from the Particle Data Group that follow an exponentially increasing mass spectrum. However, it has been suggested that even further states predicted from Quark Models are needed in the hadronic spectrum in order to improve the agreement between the hadron resonance gas model predictions and lattice QCD data. We find that the inclusion of such states with extrapolated branching ratios slightly decreases the freezeout temperature. To eliminate ambiguities, we introduce a first principle method to extract the freeze-out temperature for charged kaons from experimental data, which yields a lower bound of $T_{\text{fo}} \gtrsim $145 MeV for the highest collision energy at RHIC.