JΨ suppression

✍ Scribed by P. Guibellino; M.C. Abreu; B. Alessandro; C. Alexa; R. Arnaldi; J. Astruc; M. Atayan; C. Baglin; A. Baldit; M. Bedjidian; F. Bellaiche; S. Beolè; V. Boldea; P. Bordalo; A. Bussière; V. Capony; L. Casagrande; J. Castor; T. Chambon; B. Chaurand; I. Chevrot; B. Cheynis; E. Chiavassa; C. Cicalo; M.P. Comets; S. Constantinescu; J. Cruz; A. De Falco; N. De Marco; G. Dellacasa; A. Devaux; S. Dita; O. Drapier; B. Espagnon; J. Fargeix; S.N. Filippov; F. Fleuret; P. Force; M. Gallio; Y.K. Gavrilov; C. Gerschel; P. Giubellino; M.B. Golubeva; M. Gonin; A.A. Grigorian; J.Y. Grossiord; F.F. Guber; A. Guichard; H. Gulkaninan; R. Hakobyan; R. Haroutunian; M. Idzik; D. Jouan; T.L. Karavitcheva; L. Kluberg; A.B. Kurepin; Y. Le Bornec; C. Lourenço; M. Mac Cormick; P. Macciotta; A. Marzari-Chiesa; M. Masera; A. Masoni; S. Mehrabyan; S. Mourgues; A. Musso; F. Ohlsson-Malek; P. Petiau; A. Piccotti; J.R. Pizzi; W.L. Prado da Silva; G. Puddu; C. Quintans; C. Racca; L. Ramello; S. Ramos; P. Rato-Mendes; L. Riccati; A. Romana; S. Sartori; P. Saturnini; E. Scomparin; S. Serci; R. Shahoyan; S. Silva; C. Soave; P. Sonderegger; X. Tarrago; P. Temnikov; N.S. Topilskaya; G. Usai; C. Vale; E. Vercellin; N. Willis

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 564 KB
• Volume: 71
• Category: Article
• ISSN: 0920-5632
• DOI: 10.1016/s0920-5632(98)00354-5

✦ Synopsis

The cross section for J/~ production in Pb-Pb interactions at 158 GeV per nucleon is measured at the CERN SPS by the NA50 experiment. The final results from the 1995 run are presented here together with preliminary ones from the high-statistics 1996 run.

An anomalous J/q1 suppression is observed in Pb-Pb collisions as compared to extrapolations of the previous results obtained by the NA38 experiment with proton and lighter ion beams. The results of the two runs are in good agreement. The results from the 1996 run allow the study of the onset of the anomalous suppression within the same set of data, showing evidence of a sharp change of behaviour around a value of neutral transverse energy, as measured by our electromagnetic calorimeter, of about 50 GeV.