  We discuss how the spectral changes of quarkonia at T_c can reflect the
``critical'' behaviour of QCD phase transition. Starting from the temperature
dependencies of the energy density and pressure from lattice QCD calculation,
we extract the temperature dependencies of the scalar and spin 2 gluon
condensates near T_c. We also parameterize these changes into the electric and
magnetic condensate near T_c. While the magnetic condensate hardly changes
across T_c, we find that the electric condensate increases abruptly above T_c.
Similar abrupt change is also seen in the scalar condensate. Using the QCD
second-order Stark effect and QCD sum rules, we show that these sudden changes
induce equally abrupt changes in the mass and width of J/psi, both of which are
larger than 100 MeV at slightly above T_c.

High Energy Physics - Phenomenology