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1. The production of $\rho$ , $\omega$ and $\phi$ vector-mesons by protons and sulphur ions with incident momentum of 200 GeV/c per nucleon

Author: J. Castor, X. Tarrago, P. Bordalo, A. Romana, J.-R. Pizzi, Brigitte Cheynis, A. Baldit, A. Devaux, O. Drapier, B. Chaurand, R. Ferreira, G. Borges, M.C. Abreu, C. Gerschel, J. Astruc, Bruno Espagnon, Ruben Shahoyan, J. Guimaraes, Helena Santos, S. Ramos, C. Baglin, I. Chevrot, C. Quintans, R. Haroutunian, P. Force, Carlos Lourenco, L. Kluberg, J.-Y. Grossiord, M. Bedjidian, A. Bussiere, P. Saturnini, S. Mourgues, P. Petiau, P. Sonderegger, D. Jouan, A. Guichard, and J. Fargeix
Subjects: Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, 010308 nuclear & particles physics, Sigma, 01 natural sciences, 7. Clean energy, Omega, Spectral line, Nuclear physics, Momentum, 0103 physical sciences, Transverse mass, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon, Engineering (miscellaneous)
Abstract: The production of $\rho$ , $\omega$ and $\phi$ vector-mesons, detected through their $\mu\mu$ decay channel, is studied in p-W, S-S, S-Cu and S-U reactions at 200 GeV/c per nucleon incident momentum. Their inclusive cross-sections are determined in various transverse momentum intervals and their dependence on the projectile and target mass numbers is investigated. The relative yield $B_{\mu\mu}\sigma_{\phi}/(B_{\mu\mu}\sigma_{\rho} + B_{\mu\mu}\sigma_{\omega})$ is measured, both as a function of the transverse momentum, pT, and of the collision centrality. While this ratio exhibits no significant dependence with pT, it clearly increases with the centrality of the collision. Effective temperatures deduced from the transverse mass spectra, $d\sigma/dM_T$ , lead to values of $T_{\rho + \omega}$ equal or slightly higher than $T_{\phi}$ . Both these effective temperatures smoothly increase from p-W to S-U reactions.
Published: 2005
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2. Pseudorapidity distributions of charged particles in Pb-Pb collisions at super proton synchrotron energies from the NA50 experiment

Author: T. Claudino, J.-Y. Grossiord, Mario Sitta, Paolo Giubellino, Y.K. Gavrilov, Sergio Serci, M. Idzik, B. Espagnon, X. Tarrago, C. Castanier, Bruno Alessandro, Alexey Kurepin, A. Piccotti, G. Dellacasa, A. Baldit, Serban Constantinescu, Helena Santos, M. Masera, M. P. Comets, F. Prino, M. Mac Cormick, L. Villatte, Roberta Arnaldi, A.A. Grigorian, L. Riccati, A. Romana, Corrado Cicalo, I. Chevrot, A. De Falco, P. Bordalo, R. Hakobyan, J. Fargeix, Ermanno Vercellin, A. Bussiere, N. De Marco, S. Ramos, Stefania Beole, P. Saturnini, W.L. Prado da Silva, Calin Alexa, F. Sigaudo, O. Drapier, R. Haroutunian, M. C. Abreu, Giulio Usai, N. Willis, A. Masoni, M.B. Golubeva, A. Devaux, P. Force, G. Puddu, A. Guichard, C. Quintans, N. Constans, M. Atayan, Enrico Scalas, S. Silva, M. Bedjidian, Brigitte Cheynis, Pietro Cortese, E. Scomparin, G. Borges, T.L. Karavitcheva, S. Grigorian, P. Petiau, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, P. Sonderegger, J.-R. Pizzi, Y. Le Bornee, Marek Idzik, A. Musso, Sanda Dita, D. Jouan, M. Gonin, H.R. Gulkanyan, Mauro Gallio, V. Boldea, L. Capelli, F.F. Guber, Luciano Ramello, P. Rato Mendes, B. Chaurand, C. Gerschel, Laurent Ducroux, C. Baglin, P. Macciotta, E. Chiavassa, Ruben Shahoyan, A. Marzari-Chiesa, Marco Monteno, and J. Castor
Subjects: Physics, Particle physics, Large Hadron Collider, Nuclear Theory, General Physics and Astronomy, Super Proton Synchrotron, Charged particle, Nuclear physics, Pseudorapidity, High Energy Physics::Experiment, Multiplicity (chemistry), Impact parameter, Nuclear Experiment, Nucleon
Abstract: We present the measurements of charged particle pseudorapidity distributions dNch/dη performed by the NA50 experiment in Pb-Pb collisions at the CERN SPS. Measurements were done at incident energies of 40 GeV (√s = 8.77 GeV) and 158 GeV (√s = 17.3 GeV) per nucleon over a broad impact parameter range. The multiplicity distributions are studied as a function of centrality using the number of participating nucleons(N part ), or the number of binary nucleon-nucleon collisions (Ncoll). Their values at midrapidity exhibit a linear scaling withN part at both energies. Particle yield increases approximately by a factor of 2 betweeny √s = 8.77 GeV and √s = 17.3 GeV.
Published: 2003
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3. Strangeness measurements in NA50 experiment with Pb projectiles

Author: X. Tarrago, Mario Sitta, A. Romana, Sergio Serci, Calin Alexa, A. Bussiere, Mauro Gallio, V. Boldea, O. Drapier, J. Astruc, J.-Y. Grossiord, L. Riccati, Ermanno Vercellin, W.L. Prado da Silva, N. Constans, H.R. Gulkanyan, Paolo Giubellino, C. Soave, A. Piccotti, M. Bedjidian, I. Chevrot, L. Capelli, A. Masoni, P. Petiau, B. Espagnon, S. Silva, M.B. Golubeva, F. Ohlsson-Malek, T. Chambon, N. Willis, A. Marzari-Chiesa, A. Devaux, S. Mehrabyan, A.A. Grigorian, J. Fargeix, S. Mourgues, Roberta Arnaldi, P. Sonderegger, Marco Monteno, Laurent Ducroux, J.-R. Pizzi, Marek Idzik, João Cruz, Massimo Masera, Brigitte Cheynis, S. Ramos, L. Casagrande, Enrico Scomparin, S. Filippov, Y. Le Bornec, M. Gonin, E. Chiavassa, Bruno Alessandro, I. Ropotar, A. Guichard, F.F. Guber, G. L. Usai, B. Chaurand, Ruben Shahoyan, Luciano Ramello, M.C. Abreu, P. Bordalo, C. Gerschel, R. Hakobyan, T.L. Karavitcheva, A. De Falco, N. De Marco, G. Dellacasa, R. Haroutunian, P. Saturnini, Serban Constantinescu, A. Musso, F. Bellaiche, J. Castor, François Fleuret, Corrado Cicalo, C. Baglin, Y.K. Gavrilov, P. Rato-Mendes, P. Macciotta, Carlos Lourenco, Alexey Kurepin, L. Kluberg, L. Villatte, N.S. Topilskaya, C. Racca, V. Caponi, C. Quintans, M. Atayan, M. P. Comets, A. Baldit, Sanda Dita, D. Jouan, G. Puddu, S. Beole, M. Mac Cormick, and P. Force
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Transverse plane, Particle physics, Projectile, Transverse mass, Strangeness, Low Mass
Abstract: Low mass dimuons production has been studied in Pb-Pb collisions at 158 GeV/A . φ, ρ and ω contributions are extracted in different transverse mass and transverse energy domains. Preliminary results of the 1996 run display an increase of the φ/(ρ+ω) ratio, coming from an increase of the φ. Cross sections are presented and temperatures extracted.
Published: 2000
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4. Charmonium production in Pb−Pb collisions

Author: Corrado Cicalo, P. Petiau, R. Haroutunian, P. Sonderegger, Mario Sitta, Sergio Serci, S. Filippov, P. Bordalo, A. Marzari-Chiesa, B. Espagnon, R. Hakobyan, M. Mac Cormick, Marco Monteno, Y. Le Bornec, Bruno Alessandro, I. Ropotar, Paolo Giubellino, J. Castor, Stefania Beole, A. Masoni, M. P. Comets, P. Force, M.C. Abreu, Ermanno Vercellin, F. Bellaiche, T.L. Karavitcheva, Luciano Ramello, Marek Idzik, L. Villatte, J. Astruc, F. Guber, N. Willis, François Fleuret, A. Devaux, C. Racca, W.L. Prado da Silva, A.A. Grigorian, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, A. Romana, Massimo Masera, Sanda Dita, S. Silva, J.-R. Pizzi, D. Jouan, T. Chambon, X. Tarrago, G. Dellacasa, Brigitte Cheynis, Calin Alexa, E. Chiavassa, Ruben Shahoyan, V. Caponi, A. Piccotti, C. Baglin, C. Quintans, M. Atayan, A. Baldit, P. Rato-Mendes, Serban Constantinescu, M. Bedjidian, H.R. Gulkanyan, L. Riccati, C. Soave, I. Chevrot, O. Drapier, A. Musso, P. Macciotta, A. De Falco, S. Ramos, S. Mehrabyan, P. Saturnini, A. B. Kurepin, Mauro Gallio, V. Boldea, Enrico Scomparin, M. B. Golubeva, M. Gonin, L. Capelli, S. Mourgues, Roberta Arnaldi, J.-Y. Grossiord, A. Bussiere, Laurent Ducroux, Nora De Marco, Y.K. Gavrilov, B. Chaurand, F. Ohlsson-Malek, C. Gerschel, L. Casagrande, A. Guichard, N. De Marco, G. L. Usai, J. Fargeix, N. Constans, João Cruz, and G. Puddu
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle model, Quarkonium
Published: 2000
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5. φ, ρ and ω production in Pb-Pb collisions at 158 GeV/c2 per nucleon

Author: H.R. Gulkanyan, C. Soave, Paolo Giubellino, A. Masoni, B. Espagnon, S. Silva, C. Baglin, J. Fargeix, S. Mehrabyan, I. Ropotar, Brigitte Cheynis, A. Musso, P. Petiau, L. Villatte, J.-R. Pizzi, W.L. Prado da Silva, Mario Sitta, Nicole Willis, Bruno Alessandro, P. Rato-Mendes, A. Guichard, P. Sonderegger, T. Chambon, Sergio Serci, R. Haroutunian, Enrico Scomparin, C. Racca, M. Gallio, S.N. Filippov, M. Gonin, M. P. Comets, A. Marzari-Chiesa, Y.K. Gavrilov, X. Tarrago, F. Ohlsson-Malek, Marco Monteno, Y. Le Bornec, J.-Y. Grossiord, F. Bellaiche, N. Constans, Alexey Kurepin, A. Romana, F.F. Guber, Calin Alexa, G. L. Usai, A. Baldit, Serban Constantinescu, J. Astruc, P. Macciotta, J. Castor, S. Mourgues, Roberta Arnaldi, L. Casagrande, Corrado Cicalo, V. Boldea, T.L. Karavitcheva, L. Ramello, A. Bussiere, N. De Marco, B. Chaurand, A.A. Grigorian, O. Drapier, C. Gerschel, A. Devaux, M.C. Abreau, E. Vercellin, M. Bedjidian, François Fleuret, M.B. Golubeva, L. Capelli, Massimo Masera, João Cruz, Sanda Dita, A. De Falco, D. Jouan, Laurent Ducroux, E. Chiavassa, Ruben Shahoyan, Carlos Lourenco, L. Kluberg, P. Saturnini, N.S. Topilskaya, V. Caponi, A. Piccotti, C. Quintans, M. Atayan, G. Puddu, Stefania Beole, P. Force, M. Mac Cormick, R. Hakobyan, Marek Idzik, S. Ramos, G. Dellacasa, L. Riccati, and I. Chevrot
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Nucleon
Published: 1999
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6. Fission of lead projectiles in Pb-nucleus collisions at the SPS

Author: F. Ohlsson-Malek, Ermanno Vercellin, Stefania Beole, W.L. Prado da Silva, P. Force, H.R. Gulkanyan, C. Soave, G. Dellacasa, Enrico Scalas, G. L. Usai, B. Chaurand, S. Mehrabyan, A. B. Kurepin, F.F. Guber, J. Astruc, C. Gerschel, A. Guichard, M. Mac Cormick, L. Villatte, T.L. Karavitcheva, L. Riccati, Calin Alexa, Paolo Giubellino, I. Ropotar, I. Chevrot, M. Bedjidian, O. Drapier, C. Racca, G. Puddu, Mario Sitta, R. Haroutunian, Corrado Cicalo, J. Fargeix, A. Bussiere, Sergio Serci, S. Ramos, A. Musso, Laurent Ducroux, B. Espagnon, P. Petiau, A. Masoni, Alessandro Ferretti, Y.K. Gavrilov, Enrico Scomparin, Mauro Gallio, M. Gonin, M.B. Golubeva, V. Boldea, A. Romana, P. Sonderegger, L. Capelli, A. Marzari-Chiesa, Marco Monteno, Sanda Dita, D. Jouan, Y. Le Bornec, J. Castor, S. Silva, L. Casagrande, Brigitte Cheynis, N. De Marco, N. Constans, P. Bordalo, R. Hakobyan, N. Willis, A. Devaux, Marek Idzik, A. De Falco, P. Saturnini, A. Piccotti, J.-Y. Grossiord, M.C. Abreu, S. Mourgues, Roberta Arnaldi, S.N. Filippov, João Cruz, A.A. Grigorian, A. Baldit, Serban Constantinescu, X. Tarrago, Bruno Alessandro, Pietro Cortese, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, J.-R. Pizzi, L. Ramello, T. Chambon, V. Caponi, C. Quintans, M. Atayan, M. P. Comets, F. Bellaiche, C. Baglin, P. Rato-Mendes, P. Macciotta, Massimo Masera, E. Chiavassa, Ruben Shahoyan, Chiara Oppedisano, and François Fleuret
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Lead (geology), medicine.anatomical_structure, Fission, Projectile, medicine, Nucleus
Published: 1999
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7. F, ϱ and ω production in collisions induced by deuteron and heavy ions around 200 GeV per nucleon

Author: A. De Falco, Rachid Mazini, Y. Le Bornec, O. Drapier, C. Barrière, H.R. Gulkanyan, Ermanno Vercellin, C. Soave, P. Saturnini, M. Mac Cormick, S. Silva, P. Petiau, Massimo Masera, E. Chiavassa, Ruben Shahoyan, W.L. Prado da Silva, R. Haroutunian, V. Capony, F.F. Guber, Paolo Giubellino, P. Sonderegger, G. Puddu, N. Willis, A. Devaux, M. P. Comets, T. Chambon, J. Castor, S. Mehrabyan, Brigitte Cheynis, S. Filippov, J.M. Gago, A. Bussiere, J. Guimara˜es, Petar Temnikov, P. Gorodestky, L. Fredj, X. Tarrago, J. Fargeix, A. Marzari-Chiesa, L. Casagrande, S. Beole, J. Astruc, S. Sartori, M.C. Abreu, B. Chaurand, S. Papillon, J.-Y. Grossiord, S. Serci, T.L. Karavitcheva, Y.K. Gavrilov, A. Baldit, S. Ramos, A. Romana, J.P. Guillaud, N. De Marco, R. Ferreira, C. Gerschel, C. Racca, Calin Alexa, Corrado Cicalo, B. Espagnon, Alexey Kurepin, P. Force, M. Bedjidian, A. Piccotti, Alberto Masoni, G. Dellacasa, R. Kossakowski, D. Jouan, S. Mourgues, Roberta Arnaldi, Enrico Scomparin, B. Grosdidier, M. Gonin, M.B. Golubeva, L. Riccati, I. Chevrot, T. Monteiro, R. Mandry, D. Lazic, F. Bellaiche, L. Ramello, L. Luquin, G. L. Usai, G. Landaud, Claude Charlot, R.A. Salmeron, A. Guichard, F. Ohlsson-Malek, C. Vale, C. Quintans, M. Atayan, C. Baglin, P. Rato-Mendes, Philippe Busson, P. Macciotta, Joao Varela, Bruno Alessandro, Marek Idzik, J.-R. Pizzi, François Fleuret, P. Bordalo, R. Hakobyan, João Cruz, Didier Contardo, B. Ronceux, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, F. Vazeille, A. Musso, Serban Constantinescu, A.A. Grigorian, P. Liaud, E. Descroix, Sanda Dita, Mauro Gallio, A. Borhani, and V. Boldea
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Deuterium, Nucleon, Ion
Published: 1998
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8. Anomalous suppression in PbPb interactions at 158 GeV/c per nucleon

Author: R. Haroutunian, G. Landaud, J.Y. Grossiord, F. Bellaiche, L. Ramello, P. Bordalo, A. Devaux, Paolo Giubellino, S. Silva, B. Cheynis, Petar Temnikov, C. Racca, A. Musso, V. Capony, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, Ermanno Vercellin, Corrado Cicalo, Y. Lebornec, C. Quintans, W.L. Prado da Silva, Bruno Alessandro, C. Vale, I. Chevrot, A. Romana, G. Puddu, F. Ohlsson-Malek, João Cruz, O. Drapier, Y.K. Gavrilov, J. Fargeix, A. Marzari-Chiesa, Calin Alexa, Sergio Serci, Marek Idzik, A. Bussiere, M. Bedjidian, L. Luquin, B. Chaurand, Wladyslaw Dabrowski, C. Gerschel, N. De Marco, C. Soave, A. Guichard, M.B. Golubeva, A. Piccotti, J. Castor, D. Jouan, T. Chambon, X. Tarrago, A. B. Kurepin, F.F. Guber, Serban Constantinescu, G. L. Usai, A. De Falco, J. Astruc, P. Saturnini, N. Willis, L. Riccati, Ph. Gorodetzky, A. Masoni, Stefania Beole, G. Dellacasa, J.R. Pizzi, P. Force, S. Ramos, A. Baldit, S. Sartori, M.C. Abreu, T.L. Karavitcheva, B. Espagnon, Massimo Masera, E. Chiavassa, C. Baglin, P. Rato-Mendes, P. Macciotta, P. Guaita, Sanda Dita, François Fleuret, Mauro Gallio, V. Boldea, P. Petiau, P. Sonderegger, L. Gatignon, G. Bonazzola, S. Mourgues, Enrico Scomparin, A. Borhani, and M. Gonin
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Proton, Yield (chemistry), Quark–gluon plasma, Drell–Yan process, Atomic physics, Expected value, Nucleon, Central region, Ion
Abstract: The Drell-Yan and J ψ cross-sections measured in PbPb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J ψ in PbPb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions.
Published: 1997
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9. Anomalous suppression in Pb+Pb collisions at 158×A GeV/c

Author: R. Kossakowski, S. Mourgues, Alberto Masoni, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, N. Willis, Serban Constantinescu, R. Shaoian, A. Devaux, J.-Y. Grossiord, B. Espagnon, F. Ohlsson-Malek, G. L. Usai, G. Dellacasa, Ph. Gorodetzky, Wladyslaw Dabrowski, Sanda Dita, D. Jouan, A. Piccotti, R. Haroutunian, Paolo Giubellino, T. Chambon, I. Chevrot, C. Baglin, M. Masera, E. Chiavassa, X. Tarrago, M. Bedjidian, F.F. Guber, P. Rato-Mendes, S. Serci, J.-R. Pizzi, B. Chaurand, L. Riccati, A. Borhani, V. Boldea, Bruno Alessandro, M. Ceru, C. Gerschel, L. Luquin, Luciano Ramello, J. Astruc, P. Macciotta, A. Bussiere, Marek Idzik, Ermanno Vercellin, A. Musso, J. Fargeix, A. De Falco, M.B. Golubeva, A. Marzari-Chiesa, C. Racca, F. Bellaiche, M.S. Sartori, P. Guaita, S. Ramos, P. Saturnini, P. Force, A. Romana, A. Baldit, Calin Alexa, G. Puddu, P. Petiau, M. Gallio, A. Guichard, Y. Le Bornec, G. Landaud, P. Sonderegger, M.C. Abreu, François Fleuret, Y.K. Gavrilov, T.L. Karavitcheva, M. Gonin, Enrico Scomparin, P. Bordalo, Alexey Kurepin, S. Beole, W. L. Prado Da Silva, J. Castor, N. De Marco, Corrado Cicalo, S. Silva, V. Capony, Brigitte Cheynis, O. Drapier, and Petar Temnikov
Subjects: Physics, Nuclear and High Energy Physics, Analytical chemistry, Drell–Yan process
Abstract: Cross sections for J ψ,ψ′ 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 ψ , 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 ψ′ ( J ψ ) are similar in Pb+Pb and S+U collisions.
Published: 1996
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10. ϕ, ρ andω production in collisions induced by deuteron and heavy ions at 200 A GeV/c

Author: A. Borhani, V. Boldea, S. Silva, J. Astruc, R. Kossakowski, Sanda Dita, D. Jouan, G. Landaud, C. Baglin, N. De Marco, G. Bonazzola, M. Ceru, A. Bussiere, P. Rato-Mendes, A. Piccotti, X. Tarrago, A. Guichard, S. Serci, A. Romana, Y. Le Bornec, P. Guaita, Calin Alexa, J. R. Pizzi, M. Gonin, W. Dabrowski, M. Gallio, J. Castor, F.F. Guber, François Fleuret, S. Mourgues, M.C. Abreu, R. Haroutunian, B. Chaurand, Petar Temnikov, Ph. Gorodetzky, Alberto Masoni, Luciano Ramello, T.L. Karavitcheva, C. Gerschel, Y.K. Gavrilov, A. Baldit, M.B. Golubeva, Alexey Kurepin, F. Ohlsson-Malek, J. Fargeix, A. Marzari-Chiesa, G. Dellacasa, P. Petiau, Carlos Lourenco, S. Ramos, Enrico Scomparin, O. Drapier, T. Chambon, Ermanno Vercellin, P. Sonderegger, L. Kluberg, N.S. Topilskaya, L. Luquin, C. Racca, W.L. Prado da Silva, L. Riccati, M. Masera, F. Bellaiche, Paolo Giubellino, A. De Falco, S. Beole, C. Cicalo, Na Collaborations, R. Shaoian, Bruno Alessandro, J.-Y. Grossiord, G. Puddu, I. Chevrot, Bruno Espagnon, Serban Constantinescu, Marek Idzik, P. Bordalo, A. Devaux, P. Macciotta, A. Musso, P. Force, G. L. Usai, E. Chiavassa, V. Capony, Brigitte Cheynis, M. Bedjidian, P. Saturnini, and N. Willis
Subjects: Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, Hadron, General Physics and Astronomy, Transverse mass, Strangeness production, Elementary particle, Nucleon, Quarkonium
Abstract: The production of low mass dimuons has been measured in d-C, d-U and S-U collisions at 200 GeV per nucleon, and in Pb-Pb collisions at 160 GeV per nucleon. Theϕ, ρ andω productions in S-U collision [1, 2] are extracted from a new set of data with increased statistic, and are throughϕ/(ω+ρ) ratio compared to first results on deuteron induced production. These new analyses are presented in the limitedM T domain of recent Pb-Pb measurement whose preliminary results are also presented.
Published: 1996
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11. $\phi$ production in Pb-Pb collisions at 158 GeV/c per nucleon incident momentum

Author: V. Caponi, G. L. Usai, C. Quintans, M. Atayan, Mario Sitta, Sergio Serci, P. Rato Mendes, C. Baglin, B. Chaurand, J.-Y. Grossiord, C. Gerschel, Roberta Arnaldi, A. Baldit, P. Macciotta, N. Willis, Serban Constantinescu, A. Marzari-Chiesa, Y.K. Gavrilov, A. Masoni, N. Constans, S. Grigoryan, A. Devaux, A. Bussiere, Paolo Giubellino, Alexey Kurepin, B. Espagnon, P. Bordalo, J.-R. Pizzi, H.R. Gulkanyan, F.F. Guber, R. Hakobyan, A.A. Grigorian, Mauro Gallio, V. Boldea, X. Tarrago, Massimo Masera, O. Drapier, Marco Monteno, Y. Le Bornec, C. Castanier, Laurent Ducroux, Luciano Ramello, J. Astruc, E. Chiavassa, Ruben Shahoyan, J. Fargeix, Marek Idzik, A. Piccotti, L. Capelli, João Cruz, A. Guichard, M.B. Golubeva, J. Castor, G. Borges, Ermanno Vercellin, Corrado Cicalo, A. De Falco, T.L. Karavitcheva, N. De Marco, Sanda Dita, D. Jouan, T. Claudino, P. Saturnini, W.L. Prado da Silva, F. Sigaudo, Pietro Cortese, Enrico Scalas, L. Villatte, F Prino, Carlos Lourenco, L. Riccati, Enrico Scomparin, S. Silva, L. Kluberg, N.S. Topilskaya, M. Gonin, Brigitte Cheynis, I. Chevrot, A. Romana, Calin Alexa, S. Ramos, M. P. Comets, G. Dellacasa, Helena Santos, P. Petiau, P. Sonderegger, Bruno Alessandro, M. Mac Cormick, G. Puddu, Stefania Beole, P. Force, A. Musso, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Muon, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, 16. Peace & justice, 01 natural sciences, Nuclear physics, Particle decay, Pair production, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Transverse mass, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The production of vector mesons φ , ρ and ω has been measured in Pb–Pb collisions at 158 GeV/ c per nucleon incident momentum at the CERN/SPS. The muon spectrometer of experiment NA50 detects φ , ρ and ω mesons via their μ + μ − decay channel in the collision center of mass rapidity range 0⩽ y CM ⩽1. The results reported here show that the relative production of the φ compared to the ( ρ + ω ) and the φ multiplicity per participant nucleon ( N part ) increase with the centrality of the collision. On the other hand, the ( ρ + ω ) multiplicity per participant does not exhibit any N part dependence within our errors. The inverse slope parameter as deduced from an exponential fit to the φ transverse mass distribution is 228±10 MeV. Our results are compared with those obtained by experiment NA49 and with theoretical calculations.
Published: 2003
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12. Transverse momentum distribution of J/Ψ produced in PbPb and p-A interactions at the CERN SPS

Author: N.S. Topilskaya, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, C. Baglin, A. Baldit, M. Bedjidian, S. Beolè, V. Boldea, P. Bordalo, G. Borges, A. Bussière, L. Capelli, C. Castanier, J. Castor, B. Chaurand, I. Chevrot, B. Cheynis, E. Chiavassa, C. Cicalo, T. Claudino, M.P. Comets, N. Constans, S. Constantinescu, P. Cortese, A.De Falco, G. Dellacasa, N.De Marco, A. Devaux, S. Dita, O. Drapier, L. Ducroux, B. Espagnon, J. Fargeix, P. Force, M. Gallio, Y.K. Gavrilov, C. Gerschel, P. Giubellino, M.B. Golubeva, M. Gonin, A.A. Grigorian, S. Grigorian, J.I. Grossiord, F.F. Guber, A. Guichard, H. Gulkanyan, R. Hakobyan, R. Haroutunian, M. Idzik, D. Jouan, T.L. Karavitcheva, L. Kluberg, A.B. Kurepin, Y.Le Bornec, C. Lourenço, P. Macciotta, M.Mac Cormick, A. Marzari-Chiesa, M. Masera, A. Masoni, M. Monteno, A. Musso, P. Petiau, A. Piccotti, J.R. Pizzi, W.L. Prado da Silva, F. Prino, G. Puddu, C. Quintans, L. Ramello, S. Ramos, P. Rato-Mendes, L. Riccati, A. Romana, H. Santos, P. Saturnini, E. Scalas, E. Scomparin, S. Serci, R. Shahoyan, F. Sigaudo, M. Sitta, C. Soave, P. Sonderegger, X. Tarrago, G.L. Usai, E. Vercellin, L. Villatte, and N. Willis
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Muon, Meson, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Elementary particle, Quarkonium, Nuclear physics, Transverse mass, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract: Muon pairs produced in Pb Pb interactions at 158 GeV/c per nucleon and in p-A interactions at 400 GeV/c, together with older S-U results obtained at 200 GeV/c are used to study the transverse momentum and transverse mass distributions of the J/Ψ.
Published: 2003

13. EVIDENCE FOR DECONFINEMENT FROM THE J/ψ SUPPRESSION PATTERN IN Pb-Pb COLLISIONS BY THE NA50 EXPERIMENT

Author: M. Gonin, M.P. Comets, Bruno Alessandro, Bruno Espagnon, F.F. Guber, Paolo Giubellino, S. Silva, Luciano Ramello, Brigitte Cheynis, L. Casagrande, Y.K. Gavrilov, G. Puddu, M. Masera, T. Chambon, Alexey Kurepin, N. De Marco, I. Ropotar, S. Serci, Serban Constantinescu, A. Musso, N. Constans, G. Dellacasa, L. Villatte, H.R. Gulkanyan, P. Petiau, J.-R. Pizzi, P. Saturnini, X. Tarrago, E. Chiavassa, I. Chevrot, C. Soave, A.A. Grigorian, P. Sonderegger, M.C. Abreu, Sanda Dita, D. Jouan, Marco Monteno, M. Bedjidian, A. Piccotti, A. Bussiere, F. Prino, Marek Idzik, Laurent Ducroux, G. L. Usai, T.L. Karavitcheva, V. Boldea, M.B. Golubeva, J. Castor, S. Mehrabyan, Ermanno Vercellin, A. Baldit, N. Willis, L. Capelli, P. Rato Mendes, Carlos Lourenco, B. Chaurand, J. Fargeix, L. Kluberg, N.S. Topilskaya, C. Gerschel, A. Romana, Y. Le Bornec, P. Bordalo, R. Hakobyan, Calin Alexa, A. Devaux, C. Quintans, M. Atayan, T. Claudino, Enrico Scomparin, L. Riccati, A. Marzari-Chiesa, S. Ramos, Alberto Masoni, Mario Sitta, Roberta Arnaldi, O. Drapier, J.-Y. Grossiord, A. De Falco, C. Cicalo, P. Force, M. Mac Cormick, P. Macciotta, S. Beole, M. Gallio, A. Guichard, R. Haroutunian, Ruben Shahoyan, and C. Baglin
Subjects: Physics, Particle physics, Deconfinement
Published: 2002
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14. Scaling of charged particle multiplicity in Pb–Pb collisions at SPS energies

Author: Pietro Cortese, J.Y. Grossiord, Yu.K. Gavrilov, E. Vercellin, R. Arnaldi, M. Mac Cormick, Y. Le Bornec, A. Musso, P. Rato Mendes, A. Marzari-Chiesa, Marco Monteno, Bruno Alessandro, A. Romana, M. Masera, A. Masoni, B. Chaurand, P. Sonderegger, J. Castor, G.L. Usai, C. Gerschel, M.C. Abreu, Paolo Giubellino, G. Borges, T.L. Karavitcheva, L. Riccati, L. Villatte, I. Chevrot, S. Constantinescu, R. Haroutunian, V. Boldea, C. Quintans, M. Atayan, A. Baldit, X. Tarrago, C. Castanier, A. B. Kurepin, S. Serci, Mario Sitta, B. Espagnon, M. Gallio, P. Petiau, W.L. Prado da Silva, J.-R. Pizzi, A. Devaux, F. Sigaudo, S. Ramos, M. Bedjidian, L. Capelli, P. Force, C. Alexa, H. Gulkanyan, B. Cheynis, Enrico Scomparin, R. Shahoyan, N.S. Topilskaya, S. Grigorian, T. Claudino, Enrico Scalas, O. Drapier, C. Cicalò, S. Beolè, Laurent Ducroux, F.F. Guber, G. Puddu, G. Dellacasa, Helena Santos, L. Kluberg, A. De Falco, P. Saturnini, N. Willis, S. Dita, A. Piccotti, A.A. Grigorian, F. Prino, P. Bordalo, R. Hakobyan, M. P. Comets, Marek Idzik, L. Ramello, M. Gonin, M.B. Golubeva, J. Fargeix, A. Bussiere, A. Guichard, C. Lourenço, N. De Marco, D. Jouan, N. Constans, S. Silva, E. Chiavassa, C. Baglin, P. Macciotta, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, Nuclear Theory, Binary number, 7. Clean energy, 01 natural sciences, Power law, Charged particle, Nuclear physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, High Energy Physics::Experiment, Impact parameter, Multiplicity (chemistry), 010306 general physics, Nucleon, Nuclear Experiment, Scaling, Particle Physics - Experiment
Abstract: The charged particle multiplicity distribution dN ch / dη has been measured by the NA50 experiment in Pb–Pb collisions at the CERN SPS. Measurements were done at incident energies of 40 and 158 GeV per nucleon over a broad impact parameter range. The multiplicity distributions are studied as a function of centrality using the number of participating nucleons ( N part ), or the number of binary nucleon–nucleon collisions ( N coll ). Their values at midrapidity exhibit a power law scaling behaviour given by N part 1.00 and N coll 0.75 at 158 GeV. Compatible results are found for the scaling behaviour at 40 GeV. The width of the dN ch / dη distributions is larger at 158 than at 40 GeV/nucleon and decreases slightly with centrality at both energies. Our results are compared to similar studies performed by other experiments both at the CERN SPS and at RHIC.
Published: 2002
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15. Pseudorapidity distributions of charged particles as a function of centrality in Pb–Pb collisions at 158 and 40 GeV per nucleon incident energy

Author: M. Bedjidian, S. Grigorian, Paolo Giubellino, P. Rato Mendes, H.R. Gulkanyan, A. Masoni, B. Espagnon, B. Chaurand, C. Gerschel, A. Bussiere, O. Drapier, M. Mac Cormick, A. De Falco, C. Quintans, M. Atayan, J.-R. Pizzi, Stefania Beole, P. Saturnini, M. P. Comets, G. Dellacasa, P. Force, Bruno Alessandro, G. Puddu, Laurent Ducroux, X. Tarrago, J.-Y. Grossiord, S. Silva, C. Castanier, Mario Sitta, Helena Santos, F.F. Guber, T. Claudino, M.B. Golubeva, P. Petiau, A. Musso, Ermanno Vercellin, Sergio Serci, Brigitte Cheynis, Pietro Cortese, A. Piccotti, W.L. Prado da Silva, F. Sigaudo, Luciano Ramello, Roberta Arnaldi, P. Sonderegger, F. Prino, P. Bordalo, R. Hakobyan, Massimo Masera, Carlos Lourenco, Enrico Scalas, L. Riccati, Enrico Scomparin, N. Willis, A. Marzari-Chiesa, Marco Monteno, Y. Le Bornec, J. Castor, L. Villatte, Corrado Cicalo, L. Kluberg, N.S. Topilskaya, A. Devaux, M. Gonin, I. Chevrot, A. Guichard, A.A. Grigorian, Y.K. Gavrilov, E. Chiavassa, Ruben Shahoyan, A. Romana, Alexey Kurepin, C. Baglin, Calin Alexa, S. Ramos, Sanda Dita, D. Jouan, A. Baldit, J. Fargeix, Serban Constantinescu, Marek Idzik, G. Borges, M.C. Abreu, Mauro Gallio, T.L. Karavitcheva, V. Boldea, N. De Marco, R. Haroutunian, N. Constans, L. Capelli, G. L. Usai, P. Macciotta, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, Nuclear Theory, Function (mathematics), 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, Transverse plane, Pseudorapidity, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, High Energy Physics::Experiment, Impact parameter, 010306 general physics, Nucleon, Nuclear Experiment, Particle Physics - Experiment
Abstract: The charged particle distributions dN ch / dη have been measured by the NA50 experiment in Pb–Pb collisions at the CERN SPS. Measurements have been done at incident energies of 158 and 40 GeV per nucleon over a broad impact parameter range. Results obtained with two independent centrality estimators, namely the neutral transverse energy E T and the forward energy E ZDC , are reported.
Published: 2002
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16. CHARMONIUM SUPPRESSION IN PB-PB COLLISIONS AND QUARK-GLUON DECONFINEMENT

Author: N. Constans, N. Willis, Laurent Ducroux, Bruno Alessandro, A. Bussiere, M.C. Abreu, G. Puddu, A.A. Grigorian, Y.K. Gavrilov, T. Chambon, Serban Constantinescu, P. Rato Mendes, M.P. Comets, M. Gonin, Ermanno Vercellin, T.L. Karavitcheva, J.-R. Pizzi, F.F. Guber, B. Chaurand, L. Casagrande, Alexey Kurepin, C. Gerschel, M.B. Golubeva, Marco Monteno, P. Petiau, N. De Marco, I. Chevrot, G. Dellacasa, Luciano Ramello, X. Tarrago, Y. Le Bornec, Paolo Giubellino, A. De Falco, E. Chiavassa, P. Sonderegger, A. Marzari-Chiesa, Mario Sitta, P. Saturnini, M. Masera, J. Castor, Marek Idzik, C. Quintans, S. Serci, A. Musso, M. Atayan, Enrico Scomparin, S. Ramos, S. Beole, L. Villatte, M. Gallio, A. Baldit, Bruno Espagnon, Carlos Lourenco, I. Ropotar, L. Kluberg, N.S. Topilskaya, A. Guichard, P. Bordalo, R. Haroutunian, Alberto Masoni, C. Baglin, R. Hakobyan, P. Force, A. Romana, A. Devaux, Calin Alexa, M. Mac Cormick, P. Macciotta, C. Cicalo, H.R. Gulkanyan, C. Soave, Ruben Shahoyan, J.-Y. Grossiord, O. Drapier, L. Riccati, S. Mehrabyan, Roberta Arnaldi, T. Claudino, A. Piccotti, Sanda Dita, D. Jouan, V. Boldea, L. Capelli, J. Fargeix, G. L. Usai, S. Silva, Brigitte Cheynis, M. Bedjidian, and F. Prino
Subjects: Quark, Physics, Particle physics, Deconfinement, Gluon
Published: 2001
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17. Results from the NA50 experiment on J/Ψ suppression in Pb-Pb collisions at the CERN SPS

Author: M. Monteno, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, C. Baglin, A. Baldit, M. Bedjidian, S. Beolè, V. Boldea, P. Bordalo, A. Bussière, L. Capelli, L. Casagrande, J. Castor, T. Chambon, B. Chaurand, I. Chevrot, B. Cheynis, E. Chiavassa, C. Cicalò, T. Claudino, M.P. Comets, N. Constans, S. Constantinescu, N. De Marco, A. De Falco, G. Dellacasa, A. Devaux, S. Dita, O. Drapier, L. Ducroux, B. Espagnon, J. Fargeix, 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. Gulkanyan, R. Hakobyan, R. Haroutunian, M. Idzik, D. Jouan, T.L. Karavitcheva, L. Kluberg, A.B. Kurepin, Y. Le Bornec, C. Lourenço, P. Macciotta, M. Mac Cormick, A. Marzari-Chiesa, M. Masera, A. Masoni, S. Mehrabyan, A. Musso, P. Petiau, A. Piccotti, J.R. Pizzi, F. Prino, G. Puddu, C. Quintans, S. Ramos, L. Ramello, P. Rato Mendes, L. Riccati, A. Romana, I. Ropotar, P. Saturnini, E. Scomparin, S. Serci, R. Shahoyan, S. Silva, M. Sitta, C. Soave, P. Sonderegger, X. Tarrago, N.S. Topilskaya, G.L. Usai, E. Vercellin, L. Villatte, and N. Willis
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Nuclear Theory, Hadron, Elementary particle, Quarkonium, Atomic and Molecular Physics, and Optics, Nuclear physics, Strange matter, Impact parameter, Nuclear Experiment, Nucleon
Abstract: The NA50 experiment has measured, at the CERN SPS, the dimuon production in PbPb collisions at 158 GeV/c per nucleon, following the program of the previous NA38 and NA51 experiments, performed with proton and light ion beams. The J /Ψ production has been studied by NA50 as a function of the centrality of the collisions. The results of the analyses performed on three data samples, collected from 1995 to 1998, show that for peripheral collisions the J /Ψ cross section can be understood in terms of ordinary nuclear absorption, consistently with the extrapolation of previous measurements extending from p-p to S-U. On the contrary, the central events show an anomalous J /Ψ suppression, and the pattern of J /Ψ yield versus centrality features two discontinuities that cannot be described by conventional models based on hadronic scenarios. These results can be considered as a strong indication of the creation of a new state of matter in central PbPb collisions at the SPS.
Published: 2001

18. The dependence of the anomalous $J/\psi$ suppression on the number of participant nucleons

Author: S. Beolè, P. Rato Mendes, G. Puddu, F.F. Guber, J.Y. Grossiord, B. Chaurand, Yu.K. Gavrilov, A. Bussiere, Enrico Scomparin, A. De Falco, R. Arnaldi, Paolo Giubellino, C. Gerschel, A. B. Kurepin, B. Espagnon, G.L. Usai, F. Sigaudo, L. Riccati, A. Guichard, V. Boldea, C. Quintans, M. Atayan, Mario Sitta, N. Willis, N.S. Topilskaya, P. Saturnini, N. De Marco, B. Cheynis, D. Jouan, S. Constantinescu, S. Dita, X. Tarrago, Bruno Alessandro, C. Castanier, E Scalas, H Santos, L. Capelli, I. Chevrot, N. Constans, L. Ramello, C. Alexa, M. Gonin, M. P. Comets, S. Silva, J.-R. Pizzi, J. Fargeix, C. Cicalò, A. Piccotti, M.B. Golubeva, M. Bedjidian, C. Baglin, P. Sonderegger, G. Borges, Laurent Ducroux, P. Force, S. Grigorian, A. Baldit, P. Petiau, O. Drapier, S. Ramos, T.L. Karavitcheva, H. Gulkanyan, M. Gallio, A.A. Grigorian, F. Prino, Y. Le Bornec, A. Musso, P. Macciotta, R. Haroutunian, C. Lourenço, Pietro Cortese, E. Chiavassa, A. Devaux, M. Mac Cormick, S. Serci, G. Dellacasa, M. Masera, A. Romana, A. Masoni, M.C. Abreu, R. Shahoyan, T. Claudino, A. Marzari-Chiesa, Marco Monteno, P. Bordalo, R. Hakobyan, J. Castor, E. Vercellin, L. Villatte, L. Kluberg, Marek Idzik, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Deconfinement, Nuclear and High Energy Physics, Particle physics, Transverse energy, Hadron, Nuclear Theory, 158 Gev/C, Nucleus-nucleus collisions, 01 natural sciences, Nuclear physics, Cern-sps, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Physics, Calorimeter (particle physics), Pattern, 010308 nuclear & particles physics, Zero (complex analysis), Function (mathematics), Pb-pb interactions, J-psi-suppression, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Quark–gluon plasma, High Energy Physics::Experiment, Nucleon, Glauber, Particle Physics - Experiment
Abstract: The observation of an anomalous J/psi suppression 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/psi suppression pattern as a function of the forward hadronic energy E-ZDC measured in a Zero Degree Calorimeter (ZDC). The direct connection between EZDC and the geometry of the collision allows us to calculate, within a Glauber approach, the precise relation between the number of participant nucleons N-part and E-ZDC. Then, we check if the experimental data can be better explained by a sudden or a smooth onset of the anomalous J/psi suppression as a function of the number of participants. (C) 2001 Elsevier Science B.V. All rights reserved. info:eu-repo/semantics/publishedVersion
Published: 2001
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19. Transverse flow in heavy ion interactions at the CERN SPS

Author: P. Saturnini, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, C. Baglin, A. Baldit, M. Bedjidian, S. Beolè, V. Boldea, P. Bordalo, A. Bussière, L. Capelli, L. Casagrande, C. Castanier, J. Castor, T. Chambon, B. Chaurand, I. Chevrot, B. Cheynis, E. Chiavassa, C. Cicalò, T. Claudino, M.P. Comets, N. Constans, S. Constantinescu, N. De Marco, A. De Falco, G. Dellacasa, A. Devaux, S. Dita, O. Drapier, L. Ducroux, B. Espagnon, J. Fargeix, 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. Gulkanyan, R. Hakobyan, R. Haroutunian, M. Idzik, D. Jouan, T.L. Karavitcheva, L. Kluberg, A.B. Kurepin, Y. Le Bornec, C. Lourenço, P. Macciotta, M. Mac Cormick, A. Marzari-Chiesa, M. Masera, A. Masoni, S. Mehrabyan, M. Monteno, A. Musso, P. Petiau, A. Piccotti, J.R. Pizzi, F. Prino, G. Puddu, C. Quintans, S. Ramos, L. Ramello, P.Rato Mendes, L. Riccati, A. Romana, I. Ropotar, E. Scomparin, S. Serci, R. Shahoyan, S. Silva, M. Sitta, C. Soave, P. Sonderegger, X. Tarrago, N.S. Topilskaya, G.L. Usai, E. Vercellin, L. Villatte, and N. Willis
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Large Hadron Collider, Elliptic flow, Atomic and Molecular Physics, and Optics, Nuclear physics, Strange matter, Transverse plane, Thermalisation, State of matter, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Beam (structure)
Abstract: In the search for the quark-gluon plasma at CERN SPS, several signals were observed suggesting that this new state of matter was actually produced in the interactions induced by the lead beam at 158A GeV. The transverse flow phenomena characterize the distribution of the particles in the final state of the collision, and are expected to provide some indications about the initial state. More precisly, the existence of an elliptic flow directed along the reaction plane in the case of the non central collisions of two spherical nuclei, has been proposed to probe the thermalisation of the initial state. Indeed, the NA50 collaboration has measured these kind of effects in Pb-Pb collisions at 158A GeV, and we can conclude that the thermalisation of the initial state is actually present in these interactions. Conversely, there is no evidence for such a thermalisation in the NA38 data which were obtained with the sulphur beam at 200A GeV, neither in S-S nor in S-Cu interactions.
Published: 2001

20. Transverse momentum distributions of J/$\psi$, $\psi^{\prime}$, Drell-Yan and continuum dimuons produced in Pb-Pb interactions at the SPS

Author: G.L. Usai, L. Riccati, M. Gallio, J.Y. Grossiord, Yu.K. Gavrilov, L. Kluberg, R. Arnaldi, F Ohlson-Malek, F. Bellaiche, B. Cheynis, C. Cicalò, Mario Sitta, L. Villatte, C. Quintans, M. Atayan, S. Constantinescu, X. Tarrago, João Cruz, V. Boldea, M. P. Comets, I. Chevrot, G. Dellacasa, M. Mac Cormick, J. Fargeix, E. Chiavassa, C. Baglin, C. Alexa, A. Romana, A. Masoni, G. Puddu, Marek Idzik, P. Rato-Mendes, S. Beolè, Laurent Ducroux, A. Marzari-Chiesa, R. Shahoyan, P. Macciotta, S. Ramos, A. Baldit, Marco Monteno, L. Capelli, P. Bordalo, R. Hakobyan, A. De Falco, M.C. Abreu, A. Guichard, A. Devaux, S. Mourgues, B. Chaurand, I. Ropotar, C. Gerschel, P. Saturnini, P. Petiau, P. Force, J. Castor, P. Sonderegger, H. Gulkanyan, T.L. Karavitcheva, O. Drapier, A. Piccotti, E. Vercellin, A.A. Grigorian, F. Prino, R. Haroutunian, N. Willis, A. Bussiere, S. Dita, S Mehrabyan, F.F. Guber, B. Espagnon, Enrico Scomparin, C. Soave, A. B. Kurepin, L. Ramello, M. Gonin, M.B. Golubeva, C. Lourenço, Bruno Alessandro, M. Masera, T. Chambon, S. Serci, J.-R. Pizzi, N.S. Topilskaya, S. Silva, V. Capony, M. Bedjidian, Y. Le Bornec, A. Musso, L. Casagrande, N. De Marco, D. Jouan, N. Constans, Paolo Giubellino, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Muon, Continuum (measurement), 010308 nuclear & particles physics, Nuclear Theory, Drell–Yan process, 01 natural sciences, Nuclear physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Transverse momentum, High Energy Physics::Experiment, 010306 general physics, Nucleon, Nuclear Experiment, Particle Physics - Experiment
Abstract: Muon pairs produced in Pb-Pb interactions at 158~GeV/$c$ per nucleon are used to study the transverse momentum distributions of the J/$\psi$, $\psi^{\prime}$ and dimuons in the mass continuum. In particular, the dependence of these distributions on the centrality of the Pb-Pb collision is investigated in detail.
Published: 2000
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21. Evidence for deconfinement of quarks and gluons from the $J/psi$ suppression pattern measured in Pb-Pb collisions at the CERN-SPS

Author: A. Romana, A. Masoni, L. Villatte, G. Puddu, P. Bordalo, R. Hakobyan, Laurent Ducroux, C. Soave, A. Devaux, P. Force, M.C. Abreu, S. Constantinescu, X. Tarrago, L. Casagrande, B. Chaurand, A. Guichard, O. Drapier, C. Alexa, I. Chevrot, C. Gerschel, V. Boldea, A. Piccotti, M. Bedjidian, P. Petiau, H. Gulkanyan, M. P. Comets, A.A. Grigorian, J.-R. Pizzi, C. Lourenço, A. B. Kurepin, Marek Idzik, Paolo Giubellino, S. Beolè, G. Dellacasa, F. Prino, R. Shahoyan, S. Silva, L. Ramello, M. Gonin, N. De Marco, I. Ropotar, M.B. Golubeva, N. Willis, L. Kluberg, T.L. Karavitcheva, M. Monteno, S. Dita, M. Mac Cormick, S Mehrabyan, Bruno Alessandro, Enrico Scomparin, B. Espagnon, A. De Falco, B. Cheynis, A. Bussiere, S. Mourgues, L. Capelli, N.S. Topilskaya, F.F. Guber, D. Jouan, P. Saturnini, M. Gallio, P. Sonderegger, João Cruz, S. Ramos, R. Haroutunian, T. Chambon, Y. Le Bornec, A. Musso, G.L. Usai, L. Riccati, C. Cicalò, C. Quintans, M. Atayan, J.Y. Grossiord, Yu.K. Gavrilov, R. Arnaldi, J. Fargeix, N. Constans, A. Marzari-Chiesa, M. Sitta, J. Castor, S. Serci, A. Baldit, E. Vercellin, M. Masera, C. Baglin, P. Rato-Mendes, P. Macciotta, E. Chiavassa, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, Hadron, Drell–Yan process, 01 natural sciences, Deconfinement, Nuclear physics, Strange matter, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Quark–gluon plasma, High Energy Physics::Experiment, Color confinement, Nuclear Experiment, 010306 general physics, Particle Physics - Experiment, Production rate
Abstract: The analysis of the data collected by the NA50 experiment in 1998, reported in this paper, extends and clarifies the pattern of the previously observed J/$\psi$ anomalous suppression. This new measurement, besides providing a deeper understanding of the previous observations, reveals a steady significative decrease in the J/$\psi$ production rate up to the most central Pb-Pb collisions. It clearly rules out the presently available conventional (hadronic) models of J/$\psi$ suppression, which unanimously predict a saturation of the J/$\psi$ rate for central Pb-Pb collisions. On the contrary and together with the sharp onset of the anomalous suppression previously reported, the new observation leads to a global production rate pattern which finds its natural explanation in the framework of the formation of a deconfined state of quarks and gluons.
Published: 2000
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22. Searching for QGP: the J/ψ probe in the NA50/CERN experiment

Author: S. Silva, Brigitte Cheynis, X. Tarrago, M.P. Comets, Ermanno Vercellin, L. Riccati, Y.K. Gavrilov, T. Chambon, Alexey Kurepin, A. Piccotti, Paolo Giubellino, P. Rato Mendes, M. Gallio, J.-Y. Grossiord, J. Fargeix, B. Chaurand, O. Drapier, A. Baldit, M. Masera, C. Gerschel, R. Haroutunian, A. Marzari-Chiesa, C. Baglin, S. Serci, A. Guichard, G. Dellacasa, M. Gonin, M. Bedjidian, F.F. Guber, S. Ramos, Luciano Ramello, G. L. Usai, P. Bordalo, R. Hakobyan, G. Puddu, N. De Marco, Bruno Espagnon, F. Prino, A. Musso, P. Force, A. Devaux, Laurent Ducroux, Serban Constantinescu, A. De Falco, C. Cicalo, I. Chevrot, P. Petiau, I. Ropotar, N. Willis, Ruben Shahoyan, V. Boldea, Roberta Arnaldi, Enrico Scomparin, Marco Monteno, P. Sonderegger, S. Beole, A.A. Grigorian, A. Bussiere, P. Saturnini, M. Mac Cormick, Marek Idzik, P. Macciotta, T. Claudino, Bruno Alessandro, L. Capelli, H.R. Gulkanyan, C. Soave, Mario Sitta, J. Castor, N. Constans, M.B. Golubeva, Sanda Dita, D. Jouan, Alberto Masoni, L. Villatte, S. Mehrabyan, L. Casagrande, A. Romana, Y. Le Bornec, Calin Alexa, J.-R. Pizzi, E. Chiavassa, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, C. Quintans, M. Atayan, M.C. Abreu, and T.L. Karavitcheva
Subjects: Physics, Particle physics, Large Hadron Collider, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Hadron, Phase (waves), Function (mathematics), Curvature, J/psi meson, Nuclear physics, Quark–gluon plasma, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The J/ψ production in 158 A GeV Pb-Pb interactions is studied as a function of centrality. Its pattern, after a first sharp variation around ET=40 GeV, continues to fall down and exhibits a curvature change around ET=90 GeV. This trend excludes any conventional hadronic model and is in agreement with a deconfined quark-gluon phase scenario.
Published: 2000
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23. The elliptic flow of neutral transverse energy in heavy ion interactions at SPS energies

Author: P. Sonderegger, S. Filippov, F.F. Guber, Paolo Giubellino, Corrado Cicalo, M.C. Abreu, A. De Falco, T.L. Karavitcheva, Carlos Lourenco, S. Mourgues, Roberta Arnaldi, J. Astruc, R. Haroutunian, L. Kluberg, N.S. Topilskaya, V. Caponi, I. Ropotar, Stefania Beole, R. Shaboyan, François Fleuret, Y.K. Gavrilov, G. Dellacasa, O. Drapier, T. Chambon, Laurent Ducroux, P. Force, X. Tarrago, Ermanno Vercellin, C. Quintans, M. Atayan, N. Willis, A. Devaux, Massimo Masera, W.L. Prado da Silva, J.-R. Pizzi, L. Villatte, M. P. Comets, B. Chaurand, J.-Y. Grossiord, M. Mac Cormick, A. Guichard, L. Riccati, I. Chevrot, Mauro Gallio, A. Bussiere, V. Boldea, L. Ramello, João Cruz, C. Racca, B. Espagnon, C. Gerschel, G. Puddu, S. Ramos, F. Bellaiche, M.B. Golubeva, A. Marzari-Chiesa, Marco Monteno, E. Chiavassa, G. L. Usai, F. Ohlsson-Malek, Y. Le Bornec, C. Baglin, A. Romana, P. Rato-Mendes, J. Castor, P. Macciotta, J. Fargeix, Marek Idzik, L. Capelli, A.A. Grigorian, A. Piccotti, P. Bordalo, R. Hakobyan, M. Bedjidian, Pierre Saturnini, A. Musso, Sanda Dita, D. Jouan, A. Baldit, Serban Constantinescu, A. Masoni, N. Constans, Enrico Scomparin, Bruno Alessandro, M. Gonin, Calin Alexa, H.R. Gulkanyan, C. Soave, S. Mehrabyan, A. B. Kurepin, S. Silva, Brigitte Cheynis, Mario Sitta, L. Casagrande, Sergio Serci, N. De Marco, P. Petiau, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), NA50, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Physics, Nuclear and High Energy Physics, Phase transition, Meson, 010308 nuclear & particles physics, Elliptic flow, Hadron, Elementary particle, Kinetic energy, Quarkonium, 01 natural sciences, 7. Clean energy, Nuclear physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Atomic physics, Impact parameter, Nuclear Experiment, 010306 general physics
Abstract: The threshold effect in the J/ψ suppression seen in the NA50 data in lead on lead interactions at the CERN SPS [1,2] can't be taken into account by conventional models. Other candidate models [3] use a phase transition, and therefore let suppose that the thermodynamic variables are defined everywhere that is the so-called thermalization. The in-plane elliptic flow, which has been proposed [4] in order to probe the thermalization at these beam energies, is found to be actually present in lead on lead interactions at 158A GeV/ c , but can't be observed in sulphur on sulphur at 200A GeV/ c in the NA38 data [5,6].
Published: 1999

24. Dimuon enhancement in nucleus-nucleus ultrarelativistic interactions

Author: Mario Sitta, J. Astruc, M. Gonin, F. Bellaiche, C. Baglin, S. Mehrabyan, Y.K. Gavrilov, P. Saturnini, P. Rato-Mendes, H.R. Gulkanyan, B. Cheynis, X. Tarrago, J. R. Pizzi, Paolo Giubellino, C. Soave, N. Constans, C. Gerschel, A. Baldit, C. Racca, R. Kossakowski, L. Villatte, J. Cruz, Mauro Gallio, V. Boldea, S. Silva, Stefania Beole, Bruno Alessandro, M. P. Comets, A. Romana, S. Serci, R. Hakobyan, P. Macciotta, François Fleuret, G. Puddu, A. Marzari-Chiesa, B. Chaurand, C. Cicalo, B. Espagnon, E. Scomparin, I. Chevrot, L. Kluberg, N.S. Topilskaya, C. Lourenço, L. Luquin, A. Guichard, Ruben Shahoyan, L. Capelli, G. L. Usai, P. Bordalo, L. Riccati, N. De Marco, L. Casagrande, A. Devaux, E. Chiavassa, J. Castor, S. Dita, P. Force, O. Drapier, R. Haroutunian, E. Vercellin, Laurent Ducroux, M. Mac Cormick, D. Jouan, A. Musso, A. Bussiere, I. Ropotar, V. Caponi, Y. Le Bornec, T. Chambon, Calin Alexa, A.A. Grigorian, S. Ramos, Didier Contardo, G. Dellacasa, A. Piccotti, C. Quintans, M. Atayan, M. Masera, S.N. Filippov, F. Ohlsson-Malek, S. Mourgues, W.L. Prado da Silva, M.C. Abreu, M.B. Golubeva, M. Idzik, R. Ferreira, T.L. Karavitcheva, R. Mandry, A. Bohrani, M. Monteno, M. Bedjidian, S. Constantinescu, F.F. Guber, P. Sonderegger, Luciano Ramello, Ab Kurepin, J. Varela, Alberto Masoni, P. Petiau, J.-Y. Grossiord, J. Fargeix, G. Landau, A. De Falco, Roberta Arnaldi, Ph. Gorodetzky, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), NA38, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Robert, Suzanne, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), and Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Muon, Meson, High Energy Physics::Phenomenology, Nuclear Theory, Nuclear physics, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Superposition principle, medicine.anatomical_structure, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Mass spectrum, medicine, High Energy Physics::Experiment, Nucleon, Nuclear Experiment, Nucleus, Particle Physics - Experiment
Abstract: The study of muon pairs in the mass region $1.5
Published: 1999

25. J/$\psi$ and $\psi'$ production in p, O and S induced reactions at SPS energies

Author: S. Mourgues, L. Fredj, S. Papillon, P. Sonderegger, Ph. Gorodetzky, A. Bohrani, Bruno Espagnon, S. Silva, P. Saturnini, T. Chambon, B. Chaurand, X. Tarrago, C. Gerschel, R. Kossakowski, A. Bussiere, J. Fargeix, B. Ronceux, R. Ferreira, Carlos Lourenco, L. Kluberg, J.-R. Pizzi, M. Bedjidian, Claude Charlot, J.-Y. Grossiord, A. Baldit, A. Romana, Didier Contardo, Francois Vazeille, F. Ohlsson-Malek, M.C. Abreu, L. Luquin, E. Descroix, P. Bordalo, A. Devaux, O. Drapier, A. Guichard, R. Haroutunian, D. Jouan, G. Landaud, I. Chevrot, J. Castor, J. Astruc, J.M. Gago, C. Racca, S. Ramos, R. Mandry, C. Baglin, J.P. Guillaud, Philippe Busson, P. Force, Joao Varela, François Fleuret, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), NA38, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Large Hadron Collider, Proton, 010308 nuclear & particles physics, Dictionnaries, Nuclear Theory, targeted markup XML, API DOM, 7. Clean energy, 01 natural sciences, Ion, Nuclear physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Encyclopedia, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment, Particle Physics - Experiment, C++
Abstract: The production of the \jpsi\ and \psip\ charmonia states has been studied, through their dimuon decay, in proton, Oxygen and Sulphur induced reactions, by the NA38 experiment at the CERN SPS. The proton data was collected with beams of 200 and 450~GeV, while the ion beams had an energy of 200~GeV per incident nucleon. The \jpsi\ production cross-section per nucleon-nucleon collision exhibits a remarkably continuous pattern, as a function of the product of the mass numbers of the interacting nuclei, from pp up to S-U reactions. The same pattern is observed within S-U collisions, as a function of the collision centrality. While in p-A interactions both charmonia states exhibit the same A-dependence, in \mbox{S-U} collisions the \psip\ production is very strongly suppressed.
Published: 1999
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26. Latest results from NA50 on J/ψ suppression in Pb-Pb collisions

Author: V. Caponi, Alberto Masoni, Mario Sitta, C. Quintans, M. Atayan, S. Mourgues, Roberta Arnaldi, Bruno Alessandro, A. Bussiere, A. Romana, Calin Alexa, Laurent Ducroux, Paolo Giubellino, Marco Monteno, T. Chambon, Ermanno Vercellin, F.F. Guber, Enrico Scomparin, Y. Le Bornec, Carlos Lourenco, L. Kluberg, A. Piccotti, M. Gonin, E. Chiavassa, N.S. Topilskaya, A.A. Grigorian, X. Tarrago, Marek Idzik, M. Masera, H.R. Gulkanyan, C. Soave, Luciano Ramello, J. Astruc, Y.K. Gavrilov, J.-R. Pizzi, B. Chaurand, Sanda Dita, D. Jouan, P. Force, J.-Y. Grossiord, L. Casagrande, S. Serci, G. Puddu, C. Gerschel, João Cruz, Alexey Kurepin, I. Ropotar, M.B. Golubeva, S. Mehrabyan, P. Bordalo, V. Boldea, J. Castor, R. Haroutunian, R. Hakobyan, M. Mac Cormick, F. Ohlsson-Malek, G. Dellacasa, A. Baldit, Serban Constantinescu, N. Willis, L. Capelli, M. P. Comets, L. Riccati, A. Guichard, I. Chevrot, N. De Marco, L. Villatte, A. Devaux, F. Bellaiche, A. Marzari-Chiesa, C. Racca, Corrado Cicalo, S. Beole, M.C. Abreu, S. Ramos, T.L. Karavitcheva, W. L. Prado Da Silva, B. Espagnon, O. Drapier, A. De Falco, P. Saturnini, P. Petiau, N. Constans, P. Sonderegger, S. Filippov, M. Bedjidian, J. Fargeix, A. Musso, G. L. Usai, Ruben Shahoyan, C. Baglin, P. Rato-Mendes, P. Macciotta, M. Gallio, François Fleuret, S. Silva, and Brigitte Cheynis
Subjects: Event selection, Physics, Nuclear physics, Nuclear and High Energy Physics, Transverse plane, Particle physics, Large Hadron Collider, Nuclear Experiment, Nucleon, Collision, Electromagnetic radiation, Central region
Abstract: The main goal of the NA50 experiment is to study the J/ψ suppression pattern in Pb-Pb interactions, at 158 GeV/c per nucleon at the CERN SPS. We present here the results from the 1996 (final) and 1998 (preliminary) data taking periods. They confirm and extend our previous observation that the J/ψ is anomalously suppressed from peripheral to central collisions. With new event selection procedures and different analysis techniques, we observe that in peripheral collisions the J/ψ cross section per nucleon-nucleon collision agrees with the pattern inferred from a wide range of measurements with lighter systems, from pp up to S-U. When the collisions become more central a clear departure from this behaviour is observed. The 1996 data show a sudden drop in the J/ψ production yield for ET values above 40 GeV, where ET is the neutral transverse electromagnetic energy released in the colision and measured in the EM calorimeter. The 1998 data provide a big improvement in the study of the most central region, where a second change in the pattern becomes visible.
Published: 1999

27. J/$\psi$, $\psi'$ and Drell-Yan production in S-U interactions at 200 GeV per nucleon

Author: J.-R. Pizzi, X. Tarrago, F. Ohlsson-Malek, C. Gerschel, R. Ferreira, A. Devaux, B. Espagnon, C. Baglin, M. Bedjidian, E. Descroix, A. Romana, P. Sonderegger, Ph. Gorodetzky, S. Silva, J.M. Gago, S. Papillon, Carlos Lourenco, R. Mandry, Joao Varela, L. Kluberg, J. Castor, O. Drapier, J. Astruc, B. Ronceux, S. Ramos, Claude Charlot, M.C. Abreu, Didier Contardo, L. Luquin, G. Landaud, François Fleuret, C. Racca, R. Kossakowski, S. Mourgues, A. Guichard, Philippe Busson, A. Baldit, J.P. Guillaud, T. Chambon, P. Force, P. Saturnini, D. Jouan, A. Bussière, B. Chaurand, A. Bohrani, R. Haroutunian, I. Chevrot, J. Fargeix, P. Bordalo, J.-Y. Grossiord, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA38, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Nuclear Theory, chemistry.chemical_element, Drell–Yan process, Uranium, 01 natural sciences, Nuclear physics, chemistry, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon, Particle Physics - Experiment
Abstract: A detailed study of J/ ψ , ψ ′ and Drell-Yan production in S-U collisions has been performed by experiment NA38 at the CERN SPS. This paper presents production cross sections and their centrality dependence, based on the largest sample of S-U events collected by the experiment.
Published: 1999
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28. Observation of fission in Pb-Pb interactions at 158A GeV

Author: A. Romana, Calin Alexa, Ermanno Vercellin, J.-R. Pizzi, L. Bardi, W.L. Prado da Silva, I. Chevrot, G. Landaud, F. Ohlsson-Malek, G. L. Usai, A. Defalco, Marco Monteno, Y. Lebornec, A. Piccotti, G. Dellacasa, H.R. Gulkanyan, C. Soave, Paolo Giubellino, Mauro Gallio, V. Boldea, L. Casagrande, S. Silva, J.-Y. Grossiord, C. Vale, A. Baldit, Brigitte Cheynis, Alberto Masoni, N. Willis, S. Mourgues, E. Chiavassa, Marek Idzik, G. Puddu, Bruno Alessandro, M. Masera, Ruben Shahoyan, S. Mehrabyan, T. Chambon, S. Serci, M.P. Comets, B. Espagnon, Pietro Cortese, A. Marzari-Chiesa, A. Guichard, Roberta Arnaldi, S. Ramos, X. Tarrago, F. Bellaiche, João Cruz, Y.K. Gavrilov, J. Castor, Corrado Cicalo, Alexey Kurepin, Sanda Dita, D. Jouan, O. Drapier, P. Petiau, Enrico Scomparin, C. Baglin, L. Luquin, Mario Sitta, M. Gonin, S. Beole, P. Rato-Mendes, I. Ropotar, M. Maccormick, Carlos Lourenco, A.A. Grigorian, P. Sonderegger, A. Bussiere, P. Saturnini, L. Kluberg, N.S. Topilskaya, R. Haroutunian, M.C. Abreu, L. Riccati, T.L. Karavitcheva, P. Force, J. Fargeix, M. Bedjidian, M.B. Golubeva, C. Quintans, M. Atayan, C. Racca, François Fleuret, P. Bordalo, R. Hakobyan, Serban Constantinescu, A. Devaux, A. Musso, F.F. Guber, M. P. Macciotta, Luciano Ramello, B. Chaurand, J. Astruc, C. Gerschel, and N DeMarco
Subjects: Physics, Nuclear and High Energy Physics, Cluster decay, Large Hadron Collider, 010308 nuclear & particles physics, Fission, Nuclear Theory, Detector, Charge (physics), 01 natural sciences, Calorimeter, Nuclear physics, Yield (chemistry), 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract: The NA50 experiment at the CERN SPS has been equipped with a Cerenkov quartz detector to measure the charge of projectilelike fragments emitted in interactions of the lead beam of $158A \mathrm{GeV}$ with a 12 mm thick lead target. A clear fission peak has been observed in the light output distribution of the fragment detector and the measured number of fission events per incident Pb ion is $(1.26\ifmmode\pm\else\textpm\fi{}0.16)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}.$ The information provided by the NA50 zero-degree calorimeter has allowed us to check that fission occurs in extremely peripheral collisions. To provide the first information about the fission mechanism, the expected yield of electromagnetic fission events in our experimental conditions has been computed: it turns out to be about $40%$ smaller than the observed one. The approximations necessarily made in our calculation as well as the contribution due to fission induced by nuclear interaction could account for such a difference.
Published: 1999

29. A test pixel vertex spectrometer to complement the NA50 dimuon spectrometer

Author: S. Mourgues, B. Espagnon, Eugenio Cantatore, P. Bordalo, C. Quintans, M. Atayan, I. Ropotar, R. Hakobyan, H.R. Gulkanyan, A. Guichard, A.M Mayevskaya, M. Campbell, M.C. Abreu, T.L. Karavitcheva, Erik H.M. Heijne, A. Baldisseri, Y.K. Gavrilov, João Cruz, A. Devaux, S. Ramos, F.F. Guber, Alexey Kurepin, A.A. Grigorian, V Danielyan, S. Mehrabyan, R. Haroutunian, S.N. Filippov, J.-Y. Grossiord, Carlos Lourenco, N.S. Topilskaya, H. Vardanyan, J.-R. Pizzi, O. Drapier, F. Staley, Laurent Ducroux, A. Baldit, J Gosset, P. Force, E. Chesi, J. Castor, P. Sonderegger, Walter Snoeys, P. Saturnini, Y Terrien, I. Chevrot, L. Casagrande, H Borel, M. Bedjidian, J. Fargeix, C. Baglin, S. Silva, Brigitte Cheynis, T. Chambon, Ruben Shahoyan, A. Bussiere, M.B. Golubeva, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), NA50, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Physics, Nuclear and High Energy Physics, Vertex (computer graphics), Muon, Pixel, Spectrometer, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Nuclear Theory, Tracking (particle physics), 01 natural sciences, Particle detector, Charged particle, Nuclear physics, 0103 physical sciences, Measuring instrument, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, 010306 general physics, Instrumentation
Abstract: We have simulated the performance of a magnetic pixel vertex spectrometer, to be installed in the target area of the NA50 dimuon spectrometer. It performs well in tracking hundreds of charged particles emitted in head-on Pb–Pb collisions. The two muons among them are identified by matching their parameters to those of the muons identified in the NA50 spectrometer. A test setup of 66 000 pixels has been built. Results from a p–Be test run are presented.
Published: 1998

30. A possible evidence of Coulomb fission in lead-lead collisions at the CERN SPS

Author: S. Constantinescu, X. Tarrago, N. Willis, H.R. Gulkanyan, François Fleuret, Carlos Lourenco, L. Kluberg, F.F. Guber, N.S. Topilskaya, Sergio Serci, T. Chambon, Stefania Beole, C. Soave, C. Alexa, C. Baglin, S. Ramos, A. Baldit, P. Rato-Mendes, J.-Y. Grossiord, Y. Le Bornec, A. Musso, P. Saturnini, S.N. Filippov, P. Bordalo, L. Ramello, P. Force, S. Dita, R. Hakobyan, F. Bellaiche, Roberta Arnaldi, S. Mehrabyan, L. Bardi, A. Devaux, P. Macciotta, Massimo Masera, E. Chiavassa, Ruben Shahoyan, A. Masoni, M.P. Comets, I. Chevrot, A. Piccotti, M. Mac Cormick, Petar Temnikov, B. Chaurand, Marek Idzik, L. Riccati, L. Casagrande, J. Fargeix, C. Gerschel, M. Bedjidian, R. Haroutunian, S. Mourgues, G. Puddu, Ermanno Vercellin, Enrico Scomparin, M. Gonin, F. Ohlsson-Malek, G. L. Usai, W.L. Prado da Silva, G. Dellacasa, D. Jouan, P. Petiau, O. Drapier, A. Defalco, A. Romana, S. Sartori, M.C. Abreu, S. Silva, P. Sonderegger, V. Boldea, A. Bussiere, Paolo Giubellino, V. Capony, T.L. Karavitcheva, Mauro Gallio, Brigitte Cheynis, B. Espagnon, M.B. Golubeva, João Cruz, A. Guichard, Y.K. Gavrilov, N. Demarco, Alexey Kurepin, A.A. Grigorian, C. Vale, Bruno Alessandro, J. Astruc, C. Quintans, M. Atayan, C. Racca, Corrado Cicalo, J.-R. Pizzi, A. Marzari-Chiesa, J. Castor, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), NA50, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Physics, Cold fission, Cluster decay, Calorimeter (particle physics), Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Cherenkov detector, Fission, Nuclear Theory, Detector, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, law.invention, Nuclear physics, law, 0103 physical sciences, Coulomb, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: The NA50 experiment at CERN SPS has been equipped with a quartz Cherenkov detector to measure the charge of projectile-like fragments emitted in interactions of the lead beam of 158 AGeV with a lead target. A fission peak has been observed in the light output distribution of the fragment detector. The information provided by the NA50 zero-degree calorimeter indicates that fission occurs in extremely peripheral collisions, compatible (within the resolution of the detector) with electromagnetic interaction. The expected yield of Coulomb fission events in our experimental condition has been evaluated and turns out to be about 40% smaller than the observed one.
Published: 1998

31. NA38/NA50 results on the low mass dimuon spectra

Author: C. Soave, B. Chaurand, C. Quintans, P. Petiau, Paolo Giubellino, M. Atayan, F.F. Guber, M. Mac Cormick, W.L. Prado da Silva, P. Sonderegger, J.-R. Pizzi, O. Drapier, A. Guichard, Luciano Ramello, M. Masera, Alessandro De Falco, S. Serci, Alberto Masoni, J. Astruc, A. Romana, Y. Le Bornec, C. Gerschel, T. Chambon, A. Marzari-Chiesa, M.C. Abreu, Calin Alexa, Mauro Gallio, X. Tarrago, S.N. Filippov, V. Boldea, S. Ramos, C. Vale, S. Dita, E. Chiavassa, Ruben Shahoyan, T.L. Karavitcheva, Stefania Beole, H.R. Gulkanyan, Petar Temnikov, Y.K. Gavrilov, L. Kluberg, N.S. Topilskaya, A. Baldit, P. Force, G. Puddu, François Fleuret, G. Dellacasa, P. Bordalo, C. Baglin, S. Sartori, S. Mehrabyan, C. Racca, Ab Kurepin, P. Rato-Mendes, A. Devaux, C. Cicalo, B. Espagnon, C. Lourenço, P. Macciotta, I. Chevrot, R. Haroutunian, R. Hakobyan, Enrico Scomparin, D. Jouan, M.P. Comets, J. Castor, João Cruz, M. Gonin, E. Vercellin, S. Mourgues, A. Musso, A. Piccotti, G. L. Usai, J. Fargeix, Roberta Arnaldi, J.-Y. Grossiord, F. Bellaiche, P. Saturnini, M. Bedjidian, L. Riccati, A. Bussiere, M.B. Golubeva, A. De Falco, F. Ohlsson-Malek, L. Casagrande, M. Idzik, N. De Marco, N. Willis, S. Silva, V. Capony, Brigitte Cheynis, Bruno Alessandro, A.A. Grigorian, and Serban Constantinescu
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Antiparticle, Effective mass (solid-state physics), Pair production, Antimatter, Mass spectrum, Elementary particle, Fermion, Low Mass
Published: 1998

32. A four-dimensional deconvolution method to correct NA38 experimental data

Author: A. Guichard, T. Chambon, X. Tarrago, S. Silva, F. Ohlsson-Malek, R. Haroutunian, J. P. Guillaud, E. Descroix, B. Espagnon, J.M. Gago, L. Luquin, D. Jouan, M.C. Abreu, Didier Contardo, S. Papillon, P. Saturnini, P. Bordalo, P. Liaud, R. Kossakowski, A. Bussière, A. Devaux, D. Lazic, R. Ferreira, J.-R. Pizzi, B. Chaurand, C. Gerschel, I. Chevrot, Ph. Gorodetzky, O. Drapier, J. Castor, J.-Y. Grossiord, J. Fargeix, J. Astruc, C. Baglin, B. Ronceux, Carlos Lourenco, L. Kluberg, R. Mandry, C. Racca, S. Ramos, A. Baldit, P. Force, Joao Varela, François Fleuret, M. Bedjidian, G. Landaud, J. Guimaraes, M. Gonin, P. Petiau, A. Romana, P. Sonderegger, S. Mourgues, A. Borhani, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA38, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire d'Annecy de Physique des Particules (LAPP), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Subtraction, Experimental data, 01 natural sciences, Bayes' theorem, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Statistical analysis, Deconvolution, 010306 general physics, Instrumentation, Algorithm
Abstract: A four-dimensional method to unfold NA38 experimental distributions is presented. It is based on the Bayes theorem and uses an iterative procedure. Tests of this method on Monte-Carlo simulated distributions are described. Subtraction of the background is discussed. This method is applied to the S-U data collected in 1992 by the NA38 experiment.
Published: 1998
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33. Charmonium production in PbPb interactions at 158 GeV/c per nucleon

Author: J.Y. Grossiord, Yu.K. Gavrilov, R. Arnaldi, A. Devaux, F. Bellaiche, M. Gonin, C. Baglin, M.B. Golubeva, P. Rato-Mendes, A. De Falco, B. Cheynis, B. Espagnon, P. Macciotta, L. Casagrande, C. Cicalò, M. Atavan, F. Ohlsson-Malek, P. Saturnini, P. Sonderegger, A. Bussiere, A. Romana, A. Masoni, C. Lourenço, Marek Idzik, N. De Marco, João Cruz, A. Guichard, Enrico Scomparin, S. Ramos, D. Jouan, C. Alexa, R. Haroutunian, Paolo Giubellino, L. Kluberg, E. Chiavassa, M.C. Abreu, M. Masera, W. L. Prado Da Silva, S. Constantinescu, X. Tarrago, C. Quintans, S. Sartori, C. Soave, N.S. Topilskaya, T.L. Karavitcheva, A. Baldit, C. Racca, A. Marzari-Chiesa, A. Piccotti, M. Bedjidian, M. P. Comets, P. Force, S. Mehrabyan, A. B. Kurepin, A.A. Grigorian, S. Beolè, S. Serci, François Fleuret, G. Dellacasa, O. Drapier, J. Fargeix, M. Gallio, G. Puddu, P. Bordalo, R. Hakobyan, V. Boldea, J. Castor, B. Chaurand, G.L. Usai, C. Gerschel, E. Vercellin, Y. Le Bornec, T. Chambon, L. Riccati, A. Musso, I. Chevrot, S. Silva, V. Capony, S. Mourgues, C. Vale, F.F. Guber, J.-R. Pizzi, M. Mac Cormick, Luciano Ramello, L. Ramello, J. Astruc, N. Willis, S. Dita, P. Petiau, H. Gulkanyan, S.N. Filippov, R. Shahoyan, Petar Temnikov, and Bruno Alessandro
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Pair production, Proton, Drell–Yan process, Nucleon, Electromagnetic radiation
Abstract: The NA50 collaboration has measured J/ψ , ψ′ and Drell Yan pair production in Pb Pb interactions at 158 GeV/ c per nucleon at the CERN SPS. Final results from the 1995 run and preliminary ones from the higher statistics 1996 run are presented. A anomalous J/ψ suppression (relative to the Drell-Yan process) has been observed with respect to the suppression pattern established in experiments NA38 and NA51 with proton, oxygen and sulfur beams. The 1996 data allow a detailed study of the suppression pattern in the Pb Pb sample itself, showing a discontinuity around an E T value (the neutral transverse electromagnetic energy) of 50 GeV. The ψ′ is also suppressed relative to Drell-Yan, with a pattern very similar to the one observed in S U collisions. Finally, the p T distributions of dimuons are presented. The average p T 2 of the J/ψ in Pb Pb collisions does not increase any more with E T above 100 GeV.
Published: 1998

34. Anomalous

Author: X. Tarrago, Enrico Scomparin, A. Romana, Y. Le Bornec, Calin Alexa, G. Bonazzola, Ph. Gorodetzky, Sanda Dita, D. Jouan, Bruno Espagnon, N. De Marco, Ermanno Vercellin, F. Bellaiche, G. Puddu, J. Astruc, S. Mourgues, A. Musso, A. Borhani, V. Boldea, W.L. Prado da Silva, S. Silva, T. Chambon, C. Racca, P. Petiau, A. Piccotti, V. Capony, L. Luquin, J.-R. Pizzi, P. Sonderegger, Serban Constantinescu, Brigitte Cheynis, M. Ceru, M. Gonin, F.F. Guber, O. Drapier, J. Castor, F. Ohlsson-Malek, B. Chaurand, G. Dellacasa, C. Gerschel, Luciano Ramello, E. Chiavassa, Petar Temnikov, A. Marzari-Chiesa, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, J. Fargeix, S. Ramos, S. Sartori, A. Baldit, M.C. Abreu, A. Bussiere, T.L. Karavitcheva, G. L. Usai, M.B. Golubeva, Bruno Alessandro, Alberto Masoni, L. Riccati, A. De Falco, C. Cicalo, R. Shaoian, J.-Y. Grossiord, P. Macciotta, P. Force, S. Beole, I. Chevrot, Marek Idzik, Paolo Giubellino, M. Masera, P. Bordalo, S. Serci, A. Devaux, G. Landaud, C. Baglin, P. Rato-Mendes, P. Saturnini, Wladyslaw Dabrowski, M. Bedjidian, A. Guichard, Y.K. Gavrilov, R. Kossakowski, Alexey Kurepin, N. Willis, P. Guaita, M. Gallio, François Fleuret, and R. Haroutunian
Subjects: Quantum chromodynamics, Nuclear reaction, Physics, Particle physics, Meson, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Elementary particle, Quarkonium, Nuclear physics, Strange matter, High Energy Physics::Experiment, Nuclear Experiment, Boson
Abstract: Heavy ion production of J/ψ mesons has been studied at CERN for a decade, in search for the Quark-Gluon Plasma predicted by lattice-QCD. The suppression observed very early in O-Cu, O-U and S-U reactions has been shown to be eventually explained by nuclear absorption, and follow the same exponential behavior as the proton-nucleus reactions. The new Pb-Pb data deviate from this behavior very strongly, indicating the onset of a new regime in J/ψ suppression.
Published: 1997
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35. $J/\psi$ and Drell-Yan cross-sections in Pb-Pb interactions at 158 GeV/c per nucleon

Author: Ermanno Vercellin, J. Astruc, A. Marzari-Chiesa, A. De Falco, Paolo Giubellino, Massimo Masera, C. Soave, M. Bedjidian, A. Guichard, W.L. Prado da Silva, P. Saturnini, Ph. Gorodetzky, R. Haroutunian, G. Landaud, E. Chiavassa, N. Willis, A. Masoni, P. Bordalo, A. B. Kurepin, J.Y. Grossiord, A. Devaux, P. Guaita, J. Castor, L. Luquin, Corrado Cicalo, Sergio Serci, C. Vale, S. Silva, Calin Alexa, S. Ramos, A. Baldit, V. Capony, Wladyslaw Dabrowski, G. Puddu, François Fleuret, A. Piccotti, C. Baglin, I. Chevrot, P. Rato-Mendes, B. Cheynis, Enrico Scomparin, Carlos Lourenco, L. Kluberg, M. Gonin, C. Racca, Marek Idzik, L. Riccati, Y.K. Gavrilov, P. Macciotta, N.S. Topilskaya, L. Gatignon, G. Bonazzola, G. Dellacasa, T. Chambon, Petar Temnikov, Stefania Beole, J.R. Pizzi, F.F. Guber, P. Force, F. Ohlsson-Malek, C. Quintans, João Cruz, S. Sartori, M.C. Abreu, T.L. Karavitcheva, B. Espagnon, S. Mourgues, F. Bellaiche, L. Ramello, B. Chaurand, C. Gerschel, A. Borhani, P. Petiau, A. Bussiere, P. Sonderegger, M.B. Golubeva, J. Fargiex, Mauro Gallio, V. Boldea, A. Romana, O. Drapier, D. Jouan, G. L. Usai, Sanda Dita, X. Tarrago, Y. Le Bornec, A. Musso, Serban Constantinescu, N. De Marco, Bruno Alessandro, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), NA50, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Nuclear Theory, Drell–Yan process, 01 natural sciences, Central region, Nuclear physics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Quark–gluon plasma, High Energy Physics::Experiment, Impact parameter, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: First results are reported on J ψ and Drell-Yan cross-sections in PbPb reactions at 158 GeV/ c per nucleon. The ratio of cross-sections σ J/ψ /σ DY is studied as a function of the impact parameter of the collision estimated from the measured transverse energy.
Published: 1997
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36. Intermediate mass muon pair continuum in Pb-Pb collisions at 158 GeV/c

Author: N. De Marco, L. Luquin, A. Marzari-Chiesa, Corrado Cicalo, G. Landaud, P. Petiau, T. Chambon, S. Ramos, L. Ramello, P. Sonderegger, G. Puddu, S. Silva, V. Capony, Paolo Giubellino, X. Tarrago, Brigitte Cheynis, Ph. Gorodetzky, B. Chaurand, Ermanno Vercellin, C. Gerschel, P. Bordalo, A. Romana, W.L. Prado da Silva, A. Bussiere, G. Bonazzola, Calin Alexa, Sanda Dita, L. Riccati, S. Serci, C. Racca, D. Jouan, G. L. Usai, I. Chevrot, A. Musso, Y. Le Bornec, F. Bellaiche, M.B. Golubeva, P. Guaita, F. Ohlsson-Malek, A. Piccotti, Enrico Scomparin, J. Castor, M. Gonin, Petar Temnikov, G. Dellacasa, Marek Idzik, R. Rato-Mendes, A. Guichard, Stefania Beole, Y.K. Gavrilov, J. Fargeix, Alberto Masoni, M. Bedjidian, Alexey Kurepin, P. Force, F.F. Guber, Mauro Gallio, O. Drapier, A. Borhani, V. Boldea, J. Astruc, Bruno Alessandro, François Fleuret, Massimo Masera, A. Baldit, Serban Constantinescu, E. Chiavassa, C. Baglin, J.-R. Pizzi, M. Ceru, P. Macciotta, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, R. Haroutunian, M.S. Sartori, B. Espagnon, M.C. Abreu, T.L. Karavitcheva, R. Kossakowski, S. Mourgues, R. Shaoian, J.-Y. Grossiord, Wladyslaw Dabrowski, A. De Falco, P. Saturnini, N. Willis, and A. Devaux
Subjects: Semileptonic decay, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Muon, Large Hadron Collider, Continuum (measurement), High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Extrapolation, Nuclear physics, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment
Abstract: The NA50 experiment measures, at CERN SPS, the dimuon production in PbPb collisions at 158 GeV/c incident momentum. In this paper an analysis of the intermediate mass region (1.5⩽Mμμ⩽2.5 GeV/c2) is presented. Known dimuon sources in this interval of the spectrum are the e.m. annihilation of qq pairs (i.e. Drell-Yan) and the semileptonic decay of charmed hadrons. The contribution of these processes is calculated by means of a fit to the measured invariant mass distribution (for Drell-Yan) and of a linear extrapolation of p-A experimental results obtained by NA38 (for charm). It will be shown that known sources do not account for all of the dimuon yield measured by NA50, i.e. an excess is observed. The size of the excess measured in PbPb is larger than the one seen by NA38 in SU collisions. The centrality dependence of this effect, both in SU and PbPb, is also discussed.
Published: 1996

37. The production of $\rho$ , $\omega$ and $\phi$ vector-mesons by protons and sulphur ions with incident momentum of 200 GeV/c per nucleon.

Author: M. C. Abreu, J. Astruc, C. Baglin, A. Baldit, M. Bedjidian, P. Bordalo, G. Borges, A. Bussière, J. Castor, B. Chaurand, I. Chevrot, B. Cheynis, A. Devaux, O. Drapier, B. Espagnon, J. Fargeix, R. Ferreira, P. Force, C. Gerschel, and J.Y. Grossiord
Subjects: MESONS, PROTONS, IONS, PARTICLES (Nuclear physics), MOMENTUM (Mechanics), COLLISIONS (Physics)
Abstract: The production of $\rho$ , $\omega$ and $\phi$ vector-mesons, detected through their $\mu\mu$ decay channel, is studied in p-W, S-S, S-Cu and S-U reactions at 200 GeV/c per nucleon incident momentum. Their inclusive cross-sections are determined in various transverse momentum intervals and their dependence on the projectile and target mass numbers is investigated. The relative yield $B_{\mu\mu}\sigma_{\phi}/(B_{\mu\mu}\sigma_{\rho} + B_{\mu\mu}\sigma_{\omega})$ is measured, both as a function of the transverse momentum, p T , and of the collision centrality. While this ratio exhibits no significant dependence with p T , it clearly increases with the centrality of the collision. Effective temperatures deduced from the transverse mass spectra, $d\sigma/dM_T$ , lead to values of $T_{\rho + \omega}$ equal or slightly higher than $T_{\phi}$ . Both these effective temperatures smoothly increase from p-W to S-U reactions. [ABSTRACT FROM AUTHOR]
Published: 2005
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38. Transverse momentum distribution of J/Ψ produced in Pb - Pb interactions at 158 GeV/c per nucleon

Author: B. Chaurand, X. Tarrago, C. Gerschel, A. Bussiere, N.S. Topilskaya, V. Capony, R. Hakobyan, Brigitte Cheynis, M. P. Comets, L. Riccati, N. Willis, A. Devaux, V. Boldea, P. Macciotta, I. Chevrot, J.-R. Pizzi, F. Bellaiche, C. Alexa, A. Marzari-Chiesa, G. Puddu, Ab Kurepin, Y. Le Bornec, L. Ramello, P. Petiau, François Fleuret, Paolo Giubellino, Y.K. Gavrilov, S. Ramos, M.B. Golubeva, M. Atayan, P. Sonderegger, Bruno Alessandro, J. Castor, G. Dellacasa, D. Jouan, F. Ohlsson-Malek, H. Gulkanyan, Massimo Masera, Stefania Beole, T. Chambon, P. Bordalo, S. Dita, L. Casagrande, S. Serci, J. Fargeix, P. Force, M.C. Abreu, R. Shahoyan, C. Racca, Enrico Scomparin, A. Musso, J.I. Grossiord, C. Quintans, A. De Falco, E. Chiavassa, Mauro Gallio, P. Saturnini, M. Gonin, S. Constantinescu, F.F. Guber, C. Baglin, N. De Marco, A. Masoni, J. Astruc, P. Rato-Mendes, S. Mourgues, Roberta Arnaldi, O. Drapier, A. Baldit, C. Soave, P. Temnikov, A. Piccotti, G.L. Usai, S. Mehrabyan, A. Guichard, C. Cicalo, Carlos Lourenco, L. Kluberg, M. Mac Cormick, A. Romana, M. Bedjidian, J. Cruz, S. Silva, A.A. Grigorian, T L. Karavitcheva, Marek Idzik, S.N. Filippov, Ermanno Vercellin, W.L. Prado da Silva, S. Sartori, C. Vale, B. Espagnon, R. Haroutunian, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Centre National de la Recherche Scientifique (CNRS), NA50, Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Hadron, Nuclear Theory, Elementary particle, Quarkonium, 01 natural sciences, Nuclear physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, 010306 general physics, Nucleon, Nuclear Experiment, Boson
Abstract: International audience; The production of dimuon in Pb-Pb collisions at 158 GeV/c per nucleon has been measured at the CERN SPS in experiment NA50. An anomalous suppression of J/¢ production cross section has been observed in comparison with the value expected from the results obtained in proton and light ion induced reactions. An analysis of the transverse momentum distribution of J/¢ is presented. For J/¢ production, < p~ > values have been calculated as a function of centrality.
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