Different production sources of light nuclei in relativistic heavy-ion collisions

TL;DR

This paper introduces a combined model to analyze the production sources of light nuclei in relativistic heavy-ion collisions, revealing the dominant role of resonance decays and proposing yield ratios as key observables.

Contribution

It presents a novel combined quark and hadron recombination model to distinguish production sources of light nuclei in heavy-ion collisions.

Findings

Resonance decays significantly contribute to light nuclei regeneration.

Yield ratios like d/p and 3He/p are effective probes of production sources.

The model explains constant yield ratios across multiplicities.

Abstract

We propose a new method, i.e., an exclusive quark combination model + an inclusive hadron recombination model, to study different production sources of light nuclei in relativistic heavy-ion collisions. We take deuterons and $^3$He produced in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV as examples to present contributions of different production sources by studying their rapidity densities $dN/dy$, yield ratios and transverse momentum ($p_T$) spectra just after the hadronization as well as at the final kinetic freeze-out. We find that: only very small fractions of $d$ and $^3$He are created just after the hadronization; nucleons from $\Delta$ resonance decays make a much larger contribution to the regeneration of light nuclei at the hadronic phase stage, and this contribution takes about 79\% and 92\% for $d$ and $^3$He, respectively, observed at the final kinetic freeze-out. We also find that yield ratios $d/p$, $^3$He$/p$ and $^3$He$/d$ are good observables to probe contributions for light nuclei from different production sources, and provide a natural explanation for constant values of $d/p$ and $^3$He$/p$ as a function of the averaged charged multiplicity measured by the ALICE Collaboration.