Light nuclei production in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7-80 GeV from UrQMD model

TL;DR

This study uses the UrQMD model to analyze light nuclei production in gold-gold collisions across a range of energies, revealing a slight enhancement in certain yield ratios around 20 GeV and exploring temperature and ratio variations.

Contribution

It demonstrates that the UrQMD model can effectively reproduce light nuclei yields and identifies a potential fluctuation signal near 20 GeV, despite lacking a critical end point mechanism.

Findings

UrQMD reproduces experimental light nuclei yields.

A slight enhancement in ${N_{p}N_{t}}/{N_{d}^{2}}$ ratio occurs around 20 GeV.

Temperature and ratio analyses vary across rapidity regions.

Abstract

Light nuclei production in relativistic $^{197}$Au + $^{197}$Au collisions from 7.7 to 80 GeV is investigated within the Ultra-relativistic-Quantum-Molecular-Dynamics model (UrQMD) with a naive coalescence approach. The results of the production of light nuclei at midrapidity can essentially match up the experimental data and a slight enhancement of combined ratio of ${N_{p}N_{t}}/{N_{d}^{2}}$ where $N_p, N_d$ and $N_t$ represent respectively the yields of proton, deuteron and triton, which is sensitive to the neutron density fluctuations, occurs around 20 GeV. However, this enhanced ${N_{p}N_{t}}/{N_{d}^{2}}$ ratio should not be over-understood considering that the present UrQMD model is a cascade version without equation of state (EoS), i.e. there is an absence of critical end point mechanism. Furthermore, within different rapidity regions, the kinetic temperatures of different light nuclei are extracted by the Blast-wave model analysis and ratios among different light nuclei are also discussed.