Anomalous suppression in Pb+Pb collisions at 158×A GeV/c

Gonin, Michel; Abreu, M. C.; Alexa, C.; Alessandro, B.; Astruc, J.; Baglin, C.; Baldit, A.; Bellaiche, F.; Bedjidian, M.; Beole', Stefania; Borhani, A.; Boldea, V.; Bordalo, P.; Bussière, A.; Capony, V.; Castor, J.; Cerú, M.; Chambon, T.; Chaurand, B.; Chevrot, I.; Cheynis, B.; Chiavassa, Emilio Luciano; Cicalo, C.; Constantinescu, S.; Dabrowski, W.; De Falco, A.; Dellacasa, G.; De Marco, N.; Devaux, A.; Dita, S.; Drapier, O.; Espagnon, B.; Fargeix, J.; Fleuret, F.; Force, P.; Gallio, Mauro; Gavrilov, Y. K.; Gerschel, C.; Giubellino, P.; Golubeva, M. B.; Gonin, M.; Gorodetzky, P.; Grossiord, J. Y.; Guaita, P.; Guber, F. F.; Guichard, A.; Haroutunian, R.; Idzik, M.; Jouan, D.; Karavitcheva, T. L.; Kossakowski, R.; Kluberg, L.; Kurepin, A. B.; Le Bornec, Y.; Landaud, G.; Lourenço, C.; Luquin, L.; Macciotta, P.; Ohlsson Malek, F.; Marzari Chiesa, A.; Masera, Massimo; Masoni, A.; Mourgues, S.; Musso, A.; Petiau, P.; Prado da Silva, W. L.; Piccotti, A.; Pizzi, J. R.; Puddu, G.; Racca, C.; Ramello, L.; Ramos, S.; Rato Mendes, P.; Riccati, L.; Romana, A.; Sartori, M. S.; Saturnini, P.; Scomparin, E.; Shaoian, R.; Silva, S.; Serci, S.; Sonderegger, P.; Tarrago, X.; Temnikov, P.; Topilskaya, N. S.; Usai, G.; Vercellin, Ermanno; Willis, N.

doi:10.1016/S0375-9474(96)00373-9

Cross sections for J/psi,psi' source and Drell-Yan production in Pb+Pb collisions at 158×A GeV/c are presented and compared with results obtained by the NA38 and NA51 collaborations. The Pb+Pb data have been collected by the NA50 collaboration using the NA38 dimuon spectrometer. The Drell-Yan mechanism is found to scale as (Aprojectile · Btarget) in p+Btarget and Aprojectile+Btarget collisions including Pb+Pb collisions. Regarding J/psi source, an anomalous suppression is observed in Pb+Pb collisions with respect to the suppression observed in p+Btarget, O+Btarget and S+U collisions. The cross section ratios psi/psi' source are similar in Pb+Pb and S+U collisions.