J/ψ suppression and p T spectra in RHIC and LHC energy collisions

Abstract

In a hydrodynamic model, we have studied J/ψ production in Au+Au/Cu+Cu collisions at RHIC energy √ 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 threshold temperature T J/ψ . Sequential melting of charmonium states (χc, ψ′ and J/ψ), with melting temperatures Tχ c = T ψ′ ≈ 1.2Tc, T J/ψ ≈ 2Tc and feed-down fraction F ≈ 0.3, explains the PHENIX data on the centrality dependence of J/ψ suppression in Au+Au collisions. J/ψ pT spectra and the nuclear modification factor in Au+Au collisions are also well explained in the model. The model however over predict centrality dependence of J/ψ suppression in Cu+Cu collisions by 20-30%. The J/ψ pT spectra are under predicted by 20-30%. The model predict that in central Pb+Pb collisions at LHC energy, √ s=5500 GeV, J/ψ's are suppressed by a factor of ∼ 10. The model predicted J/ψ pT distribution in Pb+Pb collisions at LHC is similar to that in Au+Au collisions at RHIC. PACS numbers: PACS numbers: 25.75.-q, 25.75.Dw

Theoretical Perspective on Quarkonia from SPS via RHIC to LHC

“…which has also been deployed frequently to URHIC phenomenology [11,12,13,14,15,16,17]. It shows that a single reaction rate, Γ Q , governs both suppression and regeneration processes, driving the quarkonium number, N Q , toward it's equilibrium value (the gain term is only active if a quarkonium state can be supported at given temperature).…”