$J/\psi$ and ${\eta }_c$ in the Deconfined Plasma from Lattice QCD

Abstract

Analyzing correlation functions of charmonia at finite temperature ($T$) on $32^3\times (32-96)$ anisotropic lattices by the maximum entropy method (MEM), we find that $J/\psi$ and ${\eta }_c$ survive as distinct resonances in the plasma even up to $T\simeq 1.6T_c$ and that they eventually dissociate between $1.6T_c$ and $1.9T_c$ ($T_c$ is the critical temperature of deconfinement). This suggests that the deconfined plasma is non-perturbative enough to hold heavy-quark bound states. The importance of having sufficient number of temporal data points in MEM analyses is also emphasized.

Comments: 4 pages, 4 figures, REVTEX, version to appear in Physical Review Letters