Probing the tetrahedral $\alpha$ clusters in relativistic ${}^{16}$O + ${}^{16}$O collisions

Abstract

Relativistic ${}^{16}$O +${}^{16}$O collisions probe the Quark-Gluon Plasma formed in small systems, while their collective phenomena illuminate the structure of ${}^{16}$O. Recently, various configurations of ${}^{16}$O from \textit{ab initio} calculations were implemented in heavy-ion models, such as the hydrodynamic model and a multiphase transport model (AMPT) to study cluster effects in relativistic ${}^{16}$O +${}^{16}$O collisions. However, divergent predictions across configurations and models complicate interpretations. In this Letter, we isolate the impact of multi-nucleon correlations in relativistic ${}^{16}$O +${}^{16}$O collisions while fixing the one-body density distribution of ${}^{16}$O. Our results show that the normalized ratios $\mathrm{Norm}(v_2\{2\}/v_2\{4\})$ and $\mathrm{Norm}(v_2\{2\}/v_3\{2\})$ effectively probe the effects of one-body density (e.g., tetrahedral symmetry) and multi-nucleon correlations (e.g., $\alpha$ clusters). These observables provide critical constraints for refining heavy-ion models, essential for investigating cluster configurations in light nuclei through relativistic heavy-ion collisions.

Comments: 6 page, 4 figures