Measurements of H Λ3 and H Λ4 Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region

We report precision measurements of hypernuclei HΛ3 and HΛ4 lifetimes obtained from Au+Au collisions at sNN=3.0 GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of HΛ3 and HΛ4 midrapidity yields in Au+Au collisions at sNN=3.0 GeV. HΛ3 and HΛ4, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst) ps for HΛ3 and 218±6(stat)±13(syst) ps for HΛ4. The pT-integrated yields of HΛ3 and HΛ4 are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of HΛ4 is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the HΛ3 yield well, while underestimating the HΛ4 yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured HΛ3 and HΛ4 yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.