Debye Screening Mass at Next-to-Leading Order and CharmoniumDeconfinement in the Quark-Gluon Plasma

Debye screening mass at the next-to-leading order is studied by the resummation method based on perturbation theory at finite temperature. We find that the critical temperature for the J/ψ dissociation is 0.211 GeV. The contributions from the next-to-leading order are important, and critical temperature and chemical potential are shifted lower values.