Charmonium dissociation temperatures in lattice QCD with a finite volume technique

Dissociation temperatures of J/psi, psi' and chi(c) states play key roles in the sequential J/psi suppression scenario for high-energy heavy-ion collisions. We report on a study of charmonium dissociation temperatures in quenched lattice QCD. On anisotropic lattices, we first subtract the effects of the constant mode in finite temperature meson correlators, which have led to unphysical results in previous studies. We then extract ground and first exited state masses by diagonalizing correlation functions among different source and sink operators. To distinguish bound states from scattering states, we first compare the charmonium mass spectra under different spatial boundary conditions, and examine the shape and the volume dependence of their Bethe-Salpeter wavefunctions. From these studies, we found, so far, no sign of scattering states up to about 2.3T(c).