Charmonium in finite temperature lattice QCD

It is widely believed that the Quantum Choromodynamics (QCD) exhibits a phase transition at some temperature Tc, and quarks and gluons confined in the low temperature phase are liberated to form “quark gluon plasma”. At the beginning of 2000, CERN reported that the QGP state had been created in the heavy ion collision experiment[1]. In this experiment, the J/ψ suppression [2] is regarded as a key signal of QGP formation. More reliable inspection will be performed in RHIC project at BNL. On the theoretical side, in spite of various approaches, we are still far from definite understanding of charmonium properties near the transition and the fate of the hadronic states in the plasma phase. We investigate this problem using lattice QCD, which enables us to incorporate the nonperturbative effect of QCD.