Speakers
Description
The production of heavy quarkonia has been extensively used to probe Quark-Gluon Plasma (QGP) created in heavy ion collisions. The suppression of $J/\psi$ in a deconfined medium due to Debye color screening of the charm quark potential has been proposed as a signature of the QGP formation. Interpretation of $J/\psi$ suppression requires good understandings of both its production mechanism in elementary collisions and contribution from coalescence of uncorrelated c and $\overline{c}$ quraks in the medium. Despite decades of efforts, the $J/\psi$ production mechanism in p+p collisions is still not fully understood. $J/\psi$ measurements in p+p collisions at $\sqrt{s}$ = 500 GeV will provide additional insights into its production mechanism. On the other hand, precise measurements of the nuclear modification factor ($R_{AA}$) and elliptic flow ($v_{2}$) for $J/\psi$ over a broad kinematic range in Au+Au collisions can help better understand the feature of Debye color screening.
We report measurement of $J/\psi$ cross-section and yield dependence on event multiplicity in p+p collisions at $\sqrt{s}$ = 500 GeV using both the di-electron and di-muon channels. $J/\psi$ $R_{AA}$ and $v_{2}$ measurements in the di-muon channel in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV with the full data sample taken during RHIC 2014 run will also be presented.
