Gianluca Usai

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The NA60 experiment studies muon pair production at the CERN Super Proton Synchrotron. In this Letter we report on a precision measurement of J/psi in In-In collisions. We have studied the J/psi centrality distribution, and we have compared it with the one expected if absorption in cold nuclear matter were the only active suppression mechanism. For(More)
The Large Hadron Collider at CERN offers unprecedented challenges to the design and construction of detectors and trigger/data acquisition systems. For ATLAS, a three level trigger system has been developed to extract interesting physics signatures with a 10 rate reduction. To accomplish this, components of physics analysis traditionally deferred to(More)
We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess of pairs is observed above the yield expected from neutral meson decays. The unprecedented sample size of 360,000 dimuons and the good mass resolution of about 2% allow us to isolate the excess by subtraction of the decay(More)
The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158A GeV In-In collisions. An excess of pairs above the known meson decays has been reported before. We now present precision results on the associated transverse momentum spectra. The slope parameter Teff extracted from the spectra rises with dimuon mass up to the rho, followed(More)
We present a new measurement of J/ψ production in Pb-Pb collisions at 158 GeV/nucleon, from the data sample collected in year 2000 by the NA50 Collaboration, under improved experimental conditions with respect to previous years. With the target system placed in vacuum, the setup was better adapted to study, in particular, the most peripheral nuclear(More)
NA50 Collaboration M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, C. Baglin, A. Baldit, M. Bedjidian, S. Beolè, V. Boldea, P. Bordalo , S.R.Borenstein, G. Borges , A. Bussière, L. Capelli , J. Castor, C.Castanier , B. Chaurand, B. Cheynis, E. Chiavassa, C. Cicalò , T. Claudino, M.P. Comets, N. Constans, S. Constantinescu, P. Cortese , J. Cruz,(More)
R. Arnaldi 10, R. Averbeck 9, K. Banicz 2,4, J. Castor 3, B. Chaurand 7, C. Cicalò 1, A. Colla 10, P. Cortese 10, S. Damjanovic 4, A. David 2,5, A. De Falco 1, A. Devaux 3, A. Drees 9, L. Ducroux 6, H. En’yo 8, A. Ferretti 10, M. Floris 1, P. Force 3, A. ,Förster 2, N. Guettet 2,3, A. Guichard 6, H. Gulkanian 11, J. Heuser 8, M. Keil 2,5, L. Kluberg 2,7, C.(More)
R. Arnaldi 10, R. Averbeck 9, K. Banicz 2,4, J. Castor 3, B. Chaurand 7, C. Cicalò 1, A. Colla 10, P. Cortese 10, S. Damjanovic 4, A. David 2,5, A. De Falco 1, A. Devaux 3, A. Drees 9, L. Ducroux 6, H. En’yo 8, A. Ferretti 10, M. Floris 1, P. Force 3, A. Förster 2, N. Guettet 2,3, A. Guichard 6, H. Gulkanian 11, J. Heuser 8, M. Keil 2,5, L. Kluberg 2,7, J.(More)
The NA60 experiment has studied J/ψ production in Indium-Indium collisions at 158 A·GeV. In this paper we present an updated set of results obtained with the complete set of available statistics and an improved alignment of the vertex tracker. The centrality dependence of the J/ψ production, obtained with an analysis technique based only on the J/ψ sample,(More)
The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158 AGeV In-In collisions. A strong excess of pairs is observed above the yield expected from neutral meson decays. After subtraction of the decay sources, the shape of the resulting mass spectrum is largely consistent with a dominant contribution from ππ → ρ → μμ annihilation. The(More)