2026/07/30 by The STAR Collaboration
Physics and Astronomy · #nucl-ex #hep-ex #hep-ph #nucl-th
Main: 7 pages, 3 figures; Supplemental Note: 5 pages, 3 figures
arxiv created 2026/07/30 · arxiv updated 2026/07/31
The study of nuclei and hypernuclei production is a powerful tool to investigate the formation mechanism of loosely bound states in high-energy heavy-ion collisions. A key prediction from coalescence models is a strong suppression of the hypertriton (3Λ\rmH) compared to 3\rmHe production in small collision systems due to the larger radius of 3Λ\rmH. In this letter, the STAR collaboration reports measurements on (hyper)nuclei (3Λ\rmH, 3Λ\rmH, 3\rmHe, 3\rmHe, t) production at mid-rapidity in Ru+Ru and Zr+Zr collisions at √s_\rmNN=200 GeV as a function of collision centrality. We find that the ratios NtNp/Nd2 and S3 =(N_3Λ\rmH/N_3\rmHe)/(NΛ/Np) deviate significantly from thermal model expectations. Coalescence calculations incorporating realistic non-Gaussian wave functions for the d and 3Λ\rmH provide an improved description of the data, while Gaussian descriptions of the 3Λ\rmH wave function fail to simultaneously reproduce the measured S3 and the binding energy of 3Λ\rmH. These results suggest that the 3Λ\rmH wave function contains larger short-distance d--Λ probability than implied by a Gaussian ansatz, demonstrating the potential of heavy-ion production measurements as a probe of hypernuclear wave functions and the underlying hyperon--nucleon interaction.