  We suggest that the combined effect of screening, gluon-induced dissociation,
collisional damping, and reduced feed-down explains most of the sequential
suppression of Y(nS) states that has been observed in PbPb relative to pp
collisions at sqrt(s_NN) = 2.76 TeV. The suppression is thus a clear, albeit
indirect, indication for the presence of a qgp.
