# Particle Ratios within EPOS, UrQMD and Thermal Models at AGS, SPS and RHIC Energies

## TL;DR

This study compares particle ratios from heavy-ion collision models and experimental data across different energies, finding that the EPOS model underestimates certain ratios while UrQMD hybrid aligns well with most observed data.

## Contribution

It provides a comprehensive comparison of particle ratios from EPOS, UrQMD, and thermal models against experimental data at various energies, highlighting model agreements and discrepancies.

## Key findings

- UrQMD hybrid model agrees well with most data.
- EPOS model underestimates several particle ratios.
- Two types of phase transitions are indistinguishable in the models.

## Abstract

The particle ratios $k^+/\pi^+$, $\pi^-/K^-$, $\bar{p}/\pi^-$, $\Lambda/\pi^-$, $\Omega/\pi^-$, $p/\pi^+$, $\pi^-/\pi^+$, $K^-/K^+$, $\bar{p}/p$, $\bar{\Lambda}/\Lambda$, $\bar{\Sigma}/\Sigma$, $ \bar{\Omega}/\Omega$ measured at AGS, SPS and RHIC energies are compared with large statistical ensembles of $100,000$ events deduced from the CRMC EPOS $1.99$ and the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) hybrid model. In the UrQMD hybrid model two types of phase transitions are taken into account. All these are then confronted to the Hadron Resonance Gas Model. The two types of phase transitions are apparently indistinguishable. Apart from $k^+/\pi^+$, $k^-/\pi^-$, $\Omega/\pi^-$, $\bar{p}/\pi^+$, and $\bar{\Omega}/\Omega$, the UrQMD hybrid model agrees well with the CRMC EPOS $1.99$. Also, we conclude that the CRMC EPOS $1.99$ seems to largely underestimate $k^+/\pi^+$, $k^-/\pi^-$, $\Omega/\pi^-$, and $\bar{p}/\pi^+$.