Speaker
Description
Hypernuclei are bound nuclear systems of nucleons and hyperons. The hypernuclei production mechanism in heavy-ion collisions remains not fully understood. In particular, the hypertriton ($^3_\Lambda\mathrm{H}$), a bound state consisting of a proton, neutron, and hyperon, is the lightest known hypernucleus with a remarkably small binding energy. Precise measurements of the energy and multiplicity dependencies of the production of $^3_\Lambda\mathrm{H}$ will provide crucial information on the mechanisms of hypernuclei production.
In this presentation, we report comprehensive measurements from the STAR experiment at RHIC on the collision energy dependence of $^3_\Lambda\mathrm{H}$ mean transverse momentum ($\langle p_T \rangle$), $p_T$-integrated yield, and the yield double ratio $ S_3 = \, ^3_\Lambda\mathrm{H} / \big( ^3\mathrm{He} \times (\Lambda/p) \big) $ in mid-rapidity in Au + Au collisions at collision energies between 3 and 27 GeV, covering the region of high baryon density. Within this energy range, we also investigate the system size dependence of $S_3$ through charged-particle multiplicity. In addition to the measurements in Au+Au collisions, at the top RHIC energy ($\sqrt{s_{NN}} = 200~\mathrm{GeV}$) we also present recent results on $S_3$ from isobar (Zr+Zr and Ru+Ru) collisions. These results will be compared with model calculations, and physics implications on hypernuclei production mechanism will be discussed.
