Charmonia Production at the CERN/SPS

B. Alessandro , C. Alexa , R. Arnaldi , M. Atayan , S. Beole , V. Boldea , P. Bordalo , G. Borges , C. Castanier (1) , J. Castor (1) , B. Chaurand , B. Cheynis (2) , E. Chiavassa , C. Cicalo , M.P. Comets (3) , S. Constantinescu , P. Cortese , A. de Falco , N. de Marco , G. Dellacasa , A. Devaux (1) , S. Dita , J. Fargeix (1) , P. Force (1) , M. Gallio , C. Gerschel (3) , P. Giubellino , M.B. Golubeva , A.A. Grigoryan , S. Grigoryan , F.F. Guber , A. Guichard (2) , H. Gulkanyan , M. Idzik , D. Jouan (3) , T.L. Karavicheva , L. Kluberg , A.B. Kurepin , Y. Le Bornec (3) , C. Lourenço , M. Mac Cormick (3) , A. Marzari-Chiesa , M. Masera , A. Masoni , M. Monteno , A. Musso , P. Petiau , A. Piccotti , J.-R. Pizzi (2) , F. Prino , G. Puddu , C. Quintans , L. Ramello , S. Ramos , L. Riccati , H. Santos , P. Saturnini (1) , E. Scomparin , S. Serci , R. Shahoyan , F. Sigaudo , M. Sitta , P. Sonderegger , X. Tarrago (3) , N.S. Topilskaya , G.L. Usai , E. Vercellin , L. Villatte (3) , N. Willis (3) , T. Wu

1 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
2 IPNL - Institut de Physique Nucléaire de Lyon
3 IPNO - Institut de Physique Nucléaire d'Orsay

We present the final results of experiment NA50 on charmonia production in Pb-Pb interactions at 158 A GeV. A strong increasing suppression is observed with increasing centrality, for both the jpsi and psiprime resonances. We also present new developments regarding the jpsi and psiprime normal nuclear absorption determinations deduced from proton-nucleus data only. Their comparison with Pb-Pb results allows us to conclude that the jpsi anomalous suppression sets in at mid-centralities while the S-U results show a reasonable agreement with the p-A behavior. The psiprime suffers a significantly stronger suppression already in S-U interactions, which continuously increases in the Pb-Pb system, and is completely incompatible with the expected behavior deduced from p-A collisions.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, S. Beole, et al.. Charmonia Production at the CERN/SPS. XXXXth Rencontres de Moriond on QCD and Hadronic Interactions at High Energy, Mar 2005, La Thuile, Italy. ⟨in2p3-00025239⟩