Beam Energy Dependence of Triton Production and Yield Ratio (Nt x Np/N2d) in Au plus Au Collisions at RHIC

作者：Abdulhamid, M. I.; Aboona, B. E.; Adam, J.; Adams, J. R.; Agakishiev, G.; Aggarwal, I.; Aggarwal, M. M.; Ahammed, Z.; Aitbaev, A.; Alekseev, I.; Anderson, D. M.; Aparin, A.; Aslam, S.; Atchison, J.; Averichev, G. S.; Bairathi, V.; Baker, W.; Cap, J. G. Ball; Barish, K.; Bhagat, P.; Bhasin, A.; Bhatta, S.; Bordyuzhin, I. G.; Brandenburg, J. D.; V. Brandin, A.; Cai, X. Z.; Caines, H.; Sanchez, M. Calderon de la Barca; Cebra, D.; Ceska, J.; Chakaberia, I.; Chan, B. K.; Chang, Z.; Chatterjee, A.

来源：Physical Review Letters, 2023, 130(20): 202301.

DOI：10.1103/PhysRevLett.130.202301

• LIGHT-NUCLEI PRODUCTION
• HEAVY-ION COLLISIONS
• MULTIPLICITY DEPENDENCE
• QUANTUM CHROMODYNAMICS
• COALESCENCE MODEL
• QCD
• FLUCTUATIONS
• SEARCH
• PION

We report the triton (t) production in midrapidity (jyj < 0.5) Au + Au collisions at ffiffiffiffiffiffiffip= sNN 7.7-200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio (Nt x Np=N2d), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dNch=d eta) and follows a scaling behavior. The dNch=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 pT 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.