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The heavy quark pairs are produced early in heavy-ion collisions and experience the full evolution of the Quark-Gluon Plasma created in these collisions. J/ serves as one of the important probes to study the properties of the QGP. Using the high-statistics Ru+Ru and Zr+Zr collision data at s_ ₍₍ = 200 GeV recorded by the STAR experiment, it has been observed that the J/ yield is strongly suppressed and its elliptic flow is consistent with zero indicating color screening of the heavy quark-antiquark pair potential in the medium and its potentially small regeneration contribution, respectively. Besides those observables, the J/ polarization can shed new light on the QGP properties and the J/ production mechanism in heavy-ion collisions. In these proceedings, we present the first measurement of J/ polarization in heavy-ion collisions at RHIC. The study is carried out by reconstructing the J/ through its di-electron decay channel at mid-rapidity (|y| < 1). The J/ polarization parameters are measured in the Helicity frame, and Collins-Soper frame, and the spin alignment is extracted with respect to the event plane. We conclude by presenting the physics implications of this measurement.
Shen et al. (Tue,) studied this question.