1. The dependence of the anomalous J/ψsuppression on the number of participant nucleons
- Author
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Abreu, M.C, Alessandro, B, Alexa, C, Arnaldi, R, Atayan, M, Baglin, C, Baldit, A, Bedjidian, M, Beolè, S, Boldea, V, Bordalo, P, Borges, G, Bussière, A, Capelli, L, Castor, J, Castanier, C, Chaurand, B, Chevrot, I, Cheynis, B, Chiavassa, E, Cicalò, C, Claudino, T, Comets, M.P, Constans, N, Constantinescu, S, Cortese, P, De Marco, N, De Falco, A, Dellacasa, G, Devaux, A, Dita, S, Drapier, O, Ducroux, L, Espagnon, B, Fargeix, J, Force, P, Gallio, M, Gavrilov, Y.K, Gerschel, C, Giubellino, P, Golubeva, M.B, Gonin, M, Grigorian, A.A, Grigorian, S, Grossiord, J.Y, Guber, F.F, Guichard, A, Gulkanyan, H, Hakobyan, R, Haroutunian, R, Idzik, M, Jouan, D, Karavitcheva, T.L, Kluberg, L, Kurepin, A.B, Le Bornec, Y, Lourenço, C, Macciotta, P, Mac Cormick, M, Marzari-Chiesa, A, Masera, M, Masoni, A, Monteno, M, Musso, A, Petiau, P, Piccotti, A, Pizzi, J.R, Prino, F, Puddu, G, Quintans, C, Ramos, S, Ramello, L, Rato Mendes, P, Riccati, L, Romana, A, Santos, H, Saturnini, P, Scalas, E, Scomparin, E, Serci, S, Shahoyan, R, Sigaudo, F, Silva, S, Sitta, M, Sonderegger, P, Tarrago, X, Topilskaya, N.S, Usai, G.L, Vercellin, E, Villatte, L, and Willis, N
- Abstract
The observation of an anomalous J/ψsuppression in Pb–Pb collisions by the NA50 Collaboration can be considered as the most striking indication for the deconfinement of quarks and gluons at SPS energies. In this Letter, we determine the J/ψsuppression pattern as a function of the forward hadronic energy EZDCmeasured in a Zero Degree Calorimeter (ZDC). The direct connection between EZDCand the geometry of the collision allows us to calculate, within a Glauber approach, the precise relation between the number of participant nucleons Npartand EZDC. Then, we check if the experimental data can be better explained by a sudden or a smooth onset of the anomalous J/ψsuppression as a function of the number of participants.
- Published
- 2001
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