Beam energy and system size dependence of heavy flavor production at STAR

¹ State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026, China,
² Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China,

^* e-mail: wy157543@mail.ustc.edu.cn

Published online: 26 June 2024

Abstract

We report the measurements of quarkonia (J/ψ and ψ(2S)) in heavyion collisions via the e⁺e⁻ decay channel at midrapidity (|y| < 1) by the STAR experiment. The centrality and transverse momentum dependence of the yield ratio of ψ(2S) to J/ψ is measured for the first time in heavy-ion collisions at RHIC. These results, together with the new measurement of collision energy dependence of inclusive J/ψ suppression in Au+Au collisions, allow for a systematic study of the quarkonium production in the medium. In addition, we present the first measurement of J/ψ polarization in heavy-ion collisions at RHIC in both the Helicity and the Collins-Soper frames, which provides a new insight for studying the properties of the Quark-Gluon Plasma created in heavy-ion collisions.