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 A A 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 / Ψ production in most central Au + Au collisions at s N N = 200 GeV at RHIC, we find that the transportation coefficient q ˆ 0 ≃ ( 0.33 – 0.95 ) GeV 2 / fm , and, accordingly, the energy density at τ 0 is ϵ 0 ≃ ( 1.39 – 5.62 ) GeV / 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 q ˆ 0 in our estimate are in sharp contrast with those obtained by the analysis of high- p T hadron spectra in Eskola et al. (2005) [31].