Hydrodynamical model for $J/ψ$ suppression and elliptic flow

Abstract

In a hydrodynamic model, we have studied $J/ψ$ suppression and elliptic flow in Au+Au collisions at RHIC energy $\sqrt{s}$=200 GeV. At the initial time, $J/ψ$'s are randomly distributed in the fluid. As the fluid evolve in time, the free streaming $J/ψ$'s are dissolved if the local fluid temperature exceeds a melting temperature $T_{J/ψ}$. Sequential melting of charmonium states ($χ_c$, $ψ\prime$ and $J/ψ$), with melting temperatures $T_{χ_c}=T_{ψ\prime} \approx 1.2T_c$, $T_{J/ψ} \approx2T_c$ and feed-down fraction $F\approx 0.3$, is consistent with the PHENIX data on $J/ψ$ suppression and near zero elliptic flow for $J/ψ$'s. It is also shown that the model will require substantial regeneration of charmoniums, if the charmonium states dissolve at temperature close to the critical temperature, $T_{χ_c}=T_{ψ\prime} \leq T_c$, $T_{J/ψ}\approx1.2T_c$. The regenerated charmoniums will have positive elliptic flow.