On heavy-quarkonia suppression by final-state multiple scatterings in most central Au+Au collisions at RHIC

Abstract

We study heavy-quarkonia suppression under final-state multiple scatterings in most central Au~+~Au collisions at RHIC energy. We first calculate the survival probability of a heavy quarkonium under multiple scattering in Bjorken's expanding QGP at large $N_c$. Then, we calculate the rapidity dependence of the nuclear modification factor $R_{AA}$ for heavy-quarkonia production by considering final-state multiple scatterings in most central Au~+~Au collisions in a simplified model. In our formula a constant $P_0$ is also introduced to estimate the possible cold nuclear effects. By fitting the data for $J/\Psi$ production in most central Au + Au collisions at $\sqrt{s_{NN}}=200$~GeV at RHIC, we find that the transportation coefficient ${\hat{q}}_0\simeq (0.33-0.95)\text{mbox}{GeV}^2$/fm, and, accordingly, the energy density at ${\tau }_0$ is ${ϵ}_0\simeq (1.39-5.62)\text{mbox}GeV/\text{mbox}{fm}^3$ in perturbative thermal QCD. A better understanding of cold nuclear effects is essential for us to get a more accurate analysis. The small values of the transportation coefficient ${\hat{q}}_0$ in our estimate are in sharp contrast with those obtained by the analysis of high-$p_T$ hadron spectra in Ref. [31].

Comments: 20 pages, 8 figures, final version accepted for publication in Nuclear Physics A