NA60 results on $p_T$ spectra and the $\rho$ spectral function in In-In collisions

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. The unprecedented sample size of close to 400K events and the good mass resolution of about 2% have made it possi...

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Detalles Bibliográficos
Autores principales: Seixas, J, Arnaldi, R, Averbeck, R, Banicz, K, Castor, J, Chaurand, B, Cicalò, C, Colla, A, Cortese, P, Damjanovic, S, David, A, De Falco, A, Devaux, A, Drees, A, Ducroux, L, Enyo, H, Ferretti, A, Floris, M, Förster, A, Force, P, Guettet, N, Guichard, A, Gulkanian, o H, Keil, M, Kluberg, L, Lourenço, C, Lozano, J, Manso, F, Masoni, A, Martins, P, Neves, A, Ohnishi, H, Oppedisano, C, Parracho, P, Pillot, P, Puddu, G, Radermacher, E, Ramalhete, P, Rosinsky, P, Scomparin, E, Serci, S, Shahoyan, R, Sonderegger, P, Specht, H J, Tieulent, R, Usai, G, Veenhof, R, Wöhri, H K
Lenguaje:eng
Publicado: 2007
Materias:
Nuclear Physics - Experiment
Acceso en línea:https://dx.doi.org/10.1088/0954-3899/34/8/S148
http://cds.cern.ch/record/1037423
Descripción
Sumario: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. The unprecedented sample size of close to 400K events and the good mass resolution of about 2% have made it possible to isolate the excess by subtraction of the decay sources (keeping the $\rho$). The shape of the resulting mass spectrum exhibits considerable broadening, but essentially no shift in mass. The acceptance-corrected transverse-momentum spectra have a shape atypical for radial flow and show a significant mass dependence, pointing to different sources in different mass regions.

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