Production characteristics of light (anti-)nuclei from (anti-)nucleon coalescence in heavy ion collisions at energies employed at the RHIC beam energy scan

TL;DR

This study models the production of light nuclei and antinuclei in heavy ion collisions at RHIC energies using a coalescence mechanism, successfully reproducing experimental spectra and analyzing yield ratios to understand production characteristics.

Contribution

It provides analytic formulas for light nuclei momentum distributions and demonstrates the dominance of the coalescence mechanism in their production at RHIC energies.

Findings

Successfully reproduces experimental $p_T$ spectra of light nuclei.

Explains energy dependence of light nuclei yield ratios.

Highlights importance of correcting hyperon decay contributions.

Abstract

With the kinetic freeze-out nucleons and antinucleons obtained from the quark combination model, we study the production of light nuclei and antinuclei in the (anti-)nucleon coalescence mechanism in relativistic heavy ion collisions. We derive analytic formulas of the momentum distributions of different light nuclei and apply them to compute transverse momentum ($p_T$) spectra of (anti-)deuterons ($d$, $\bar d$) and (anti-)tritons ($t$, $\bar t$) in Au-Au collisions at $\sqrt{s_{NN}}=$7.7, 11.5, 19.6, 27, 39, 54.4 GeV. We find that the experimental data available for these $p_T$ spectra can be well reproduced. We further study the yields and yield ratios of different light (anti-)nuclei and naturally explain their interesting behaviors as a function of the collision energy. We especially point out that the multi-particle yield ratio $tp/d^2$ should be carefully corrected from hyperon weak decays for protons to probe the production characteristics of light nuclei. All of our results show that the coalescence mechanism for (anti-)nucleons plays a dominant role for the production of light nuclei and antinuclei at the RHIC beam energy scan energies.