Mass Shift of Charmonium near Deconfining Temperature and Possible Detection in Lepton-Pair Production

The mass shift of charmonium near the critical temperature of the deconfining transition is investigated by a c-c̄ potential model through the change of the string tension. On the basis of the results, detection of the shift by lepton-pair production is discussed by the use of the hydrodynamical model of ultrarelativistic nucleus-nucleus collisions. It is shown that the mass shift is detectable if the critical temperature is not lower than 300 MeV.