Charmonium states in QGP

Motivated by recent lattice gauge results that the quarkonium does not dissolve at the critical temperature, we report on recent developments in understanding the properties of charmonium states in the quark gluon plasma using perturbative QCD and QCD sum rule approaches. Using lattice results on the energy density and pressure of pure gauge theory as inputs to the operator product expansion in these theories, we find non trivial property changes of heavy quarkonium across the phase transition.