J/psi suppression in heavy ion collisions - interplay of hard and soft   QCD processes
  We study J/psi suppression in AB collisions assuming that the charmonium states evolve from small, color transparent configurations. Their interaction with nucleons and nonequilibrated, secondary hadrons is simulated using the microscopic model UrQMD. The Drell-Yan lepton pair yield and the J/psi/Drell-Yan ratio are calculated as a function of the neutral transverse energy in Pb+Pb collisions at 160 GeV and found to be in reasonable agreement with existing data. 
C. Spieles, R. Vogt, L. Gerland, S.A. Bass, M. Bleicher, L. Frankfurt,   M. Strikman, H. Stoecker, W. Greiner