Energy dependence of light hypernuclei production in heavy-ion collisions from a coalescence and statistical-thermal model perspective
Tom Reichert, Jan Steinheimer, Volodymyr Vovchenko, Benjamin Dönigus, Marcus Bleicher
Abstract
A comparison of light hypernuclei production, from Ultra-relativistic Quantum Molecular Dynamics (UrQMD)$+\text{coalescence}$ 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 $\mathrm{\ensuremath{\Lambda}}$ are affected by both the source radius $\mathrm{\ensuremath{\Delta}}r$ 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 are 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 ($\mathrm{\ensuremath{\Lambda}}\mathrm{\ensuremath{\Lambda}}$) seems ruled out by ALICE data.