Properties of J/ψ at Tc: QCD second-order Stark effect

Starting from the temperature dependencies of the energy density and pressure from lattice QCD calculation, we extract the temperature dependencies of the electric and magnetic condensate near Tc. While the magnetic condensate hardly changes across Tc, we find that the electric condensate increases abruptly above Tc. This induces a small but equally abrupt decrease in the mass of J/ψ, which can be calculated through the second-order Stark effect. Combining the present result with the previously determined QCD sum rule constraint, we extract the thermal width of J/ψ above Tc, which also increases fast. These changes can be identified as the critical behavior of J/ψ across Tc associated with the phase transition. We find that the mass shift and width broadening of J/ψ at 1.05Tc will be around -100MeV and 100 MeV, respectively.