QCD sum rules and thermal properties of Charmonium in the vector channel

The thermal evolution of the hadronic parameters of charmonium in the vector channel, i.e. the J/ψ resonance mass, coupling (leptonic decay constant), total width, and continuum threshold is analyzed in the framework of thermal Hilbert moment QCD sum rules. The continuum threshold s0, as in other hadronic channels, decreases with increasing temperature until the PQCD threshold s0=4mQ2 is reached at T≃1.22Tc (mQ is the charm quark mass) and the J/ψ mass is essentially constant in a wide range of temperatures. The other hadronic parameters behave in a very different way from those of light-light and heavy-light quark systems. The total width grows with temperature up to T≃1.04Tc beyond which it decreases sharply with increasing T. The resonance coupling is also initially constant beginning to increase monotonically around T≃Tc. This behavior strongly suggests that the J/ψ resonance might survive beyond the critical temperature for deconfinement, in agreement with lattice QCD results.