Collision Energy Dependence of Hypertriton Production in Au+Au Collisions at RHIC

The STAR Collaboration reports measurements of the collision energy dependence of hypertriton (³_ΛH) transverse momentum spectra and pT-integrated yields at mid-rapidity ($|y|<$0.5) in Au+Au collisions at 11 collision energies between 3.2 and 27\,GeV. The measured ³_ΛH yields and ³_ΛH/$Λ$ yields ratio in central collisions increase strongly with decreasing collision energy, and are a factor of ~2 lower than thermal model predictions at this energy range. The mean pT of ³_ΛH is lower than the Blast-Wave expectation using the freeze-out parameters from light hadrons. Furthermore, the observed double ratio (³_ΛH/Λ)/(t/p) maintains a constant value of ~0.4 across the measured energy range. Within the coalescence framework, this ratio directly reflects the significantly suppressed formation probability of the weakly-bound hypertriton relative to the triton, which results from the weaker hyperon-nucleon interaction compared with the nucleon-nucleon interaction.