Global Polarization of (Anti-)Hypertriton in Heavy-Ion Collisions

Particles of non-zero spin produced in non-central heavy-ion collisions are expected to be polarized along the direction perpendicular to the reaction plane because of their spin-orbit interactions in the produced matter, and this has indeed been observed for many hyperons and vector mesons. Here, we show that the hypertriton (^3_ΛH), which is the lightest hypernucleus, is also polarized in these collisions. Using the coalescence model based on the kinetic freezeout baryons for light (hyper-)nuclei production, we find that the angular distribution of the decay product of polarized ^3_ΛH is highly sensitive to the spin configuration of its wavefunction, providing a novel way to determine its spin structure. We also predict the beam energy dependence of ^3_ΛH and ^3_Λ̅ H polarizations in heavy-ion collisions from a few GeV to several TeV based on the measured Λ and Λ̅ polarizations. We further discuss the possibility of studying the spin correlations among nucleons and Λ hyperons in the produced hadronic matter from the measured ^3_ΛH polarization in non-central heavy-ion collisions.