Beam Energy Dependence of Triton Production and Yield Ratio (Nt×Np/ Nd2) in Au+Au Collisions at RHIC

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4 Scopus citations


We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at 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×Np/Nd2), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dNch/dη) and follows a scaling behavior. The dNch/dη 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 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. 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.

Original languageEnglish
Article number202301
JournalPhysical Review Letters
Issue number20
StatePublished - May 19 2023

Bibliographical note

Funding Information:
We thank Dr. L. W. Chen, Dr. C. M. Ko, Dr. V. Koch, Dr. D. Oliinychenko, Dr. J. Steinheimer, Dr. K. J. Sun, Dr. V. Vovchenko, and Dr. W. Zhao for interesting discussions about light nuclei production in heavy-ion collisions. We thank the RHIC Operations Group and RCF at BNL, the NERSC Center at LBNL, and the Open Science Grid consortium for providing resources and support. This work was supported in part by the Office of Nuclear Physics within the U.S. DOE Office of Science, the U.S. National Science Foundation, National Natural Science Foundation of China, Chinese Academy of Science, the Ministry of Science and Technology of China and the Chinese Ministry of Education, the Higher Education Sprout Project by Ministry of Education at NCKU, the National Research Foundation of Korea, Czech Science Foundation and Ministry of Education, Youth and Sports of the Czech Republic, Hungarian National Research, Development and Innovation Office, New National Excellency Programme of the Hungarian Ministry of Human Capacities, Department of Atomic Energy and Department of Science and Technology of the Government of India, the National Science Centre and WUT ID-UB of Poland, the Ministry of Science, Education and Sports of the Republic of Croatia, German Bundesministerium für Bildung, Wissenschaft, Forschung and Technologie (BMBF), Helmholtz Association, Ministry of Education, Culture, Sports, Science, and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS).

Publisher Copyright:
© 2023 American Physical Society.

ASJC Scopus subject areas

  • Physics and Astronomy (all)


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