Beam Energy Dependence of Triton Production and Yield Ratio ($\mathrm{N}_t \times \mathrm{N}_p/\mathrm{N}_d^2$) in Au+Au Collisions at RHIC

The STAR collaboration
Abdulhamid, Muhammad , Aboona, Bassam , Adam, Jaroslav , Adams, Joseph , Agakishiev, Geydar , Aggarwal, Ishu , Aggarwal, Madan , Ahammed, Zubayer , Aitbaev, Alisher , Alekseev, Igor
Phys.Rev.Lett. 130 (2023) 202301, 2023.

Abstract (data abstract)
We report the triton ($t$) production in mid-rapidity ($|y| <$ 0.5) Au+Au collisions at $\sqrt{s_\text{NN}}$ = 7.7--200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider (RHIC). The nuclear compound yield ratio (\(N_t\)\(\times\)\(N_p\)/\(N_d^2\)), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dN\(_{ch}\)/d\(\eta\)) and follows a scaling behavior. The dN\(_{ch}\)/d\(\eta\) dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3$\sigma$ and 3.4$\sigma$, respectively, giving a combined significance of 4.1$\sigma$. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_{T}$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

Loading Data...