Energy dependence of light hypernuclei production in heavy-ion collisions from a coalescence and statistical-thermal model perspective

TL;DR

This study compares hypernuclei production in heavy-ion collisions using coalescence and thermal models across various energies and system sizes, highlighting how different ratios depend on source size and canonical effects.

Contribution

It provides a detailed comparison of coalescence and thermal models for hypernuclei production, identifying key factors influencing hypertriton ratios and constraining source size effects.

Findings

Both models yield similar results with specific differences.

The hypertriton to Lambda ratio depends on source radius and canonical effects.

The double ratio S_3 is nearly independent of canonical effects.

Abstract

A comparison of light hypernuclei production, from UrQMD+coalescence and the thermal model, in heavy ion collisions over a wide range of beam energies and system sizes is presented. We find that both approaches provide generally similar results, with differences in specific details. Especially the ratios of hypertriton to $\Lambda$ are affected by both the source radius $\Delta r$ of the coalescence procedure as well as canonical effects. On the other hand, the double ratio $S_3$ is almost independent of canonical effects, which is in contrast to coalescence. Thus, both the beam energy dependence and centrality dependence of $S_3$ can be used to constrain the hypertriton source radius. To do so the currently available data is not yet sufficient. Elliptic flow is shown to be unaffected by the source size of the nuclei and an almost perfect mass scaling of the elliptic flow is observed. Our predictions further suggest that the existence of the H-dibaryon ($\Lambda\Lambda$) seems ruled out by ALICE data.