In this Letter we report the first results on π±, K±, p, and p̄ production at midrapidity (|y|<0.5) in central Pb-Pb collisions at √sNN=2.76TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at √sNN=200GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with √sNN, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood. © 2012 CERN. Published by the American Physical Society.

Pion, kaon, and proton production in central Pb-Pb collisions at √sNN=2.76TeV

BASU, SUJIT;BRUNO, GIUSEPPE EUGENIO;CARMINATI, FLAVIO;COSTA, FIAMMETTA;DAS, KESHABANANDA;DI BARI, DEBORAH;FERRETTI, ANDREA;MULLER, HEIKO;PERINI, DAVIDE;ROY, PARTHA PRATIM;SEGATO, GINO;TOIA, ALESSIO;
2012

Abstract

In this Letter we report the first results on π±, K±, p, and p̄ production at midrapidity (|y|<0.5) in central Pb-Pb collisions at √sNN=2.76TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at √sNN=200GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with √sNN, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood. © 2012 CERN. Published by the American Physical Society.
PHYSICAL REVIEW LETTERS
http://oai.aps.org/filefetch?identifier=10.1103/PhysRevLett.109.252301&component=fulltext&description=markup&format=xml
Physics and Astronomy (all)
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11383/2062291
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