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Physical Review Letters 109 (2012) 252301
Pion, Kaon, and Proton Production in Central Pb--Pb Collisions at $\sqrt{s_{NN}} = 2.76$ TeV
B. Abelev, N. Arbor1, G. Conesa Balbastre1, J. Faivre, C. Furget1, R. Guernane1, S. Kox1, J.S. Real1, C. Silvestre1, R. Vernet2, I. Belikov3, B. Hippolyte3, C. Kuhn3, C. Roy3, X. Sanchez Castro3, S. Senyukov3, L. Aphecetche4, Guillaume Batigne4, E. Bergognon4, M. Bregant4, H. Delagrange4, O. Driga4, B. Erazmus4, M. Estienne4, M. Germain4, A. Lardeux4, F. Lefèvre4, L. Luquin4, G. Martınez Garcıa4, A. Mas4, L. Massacrier4, A. Matyja4, P. Pillot4, Y. Schutz4, A. Shabetai4, D. Stocco4, Y. .W. Baek5, A. Baldit5, V. Barret5, N. Bastid5, P. Crochet5, P. Dupieux5, R. Ichou5, X. Lopez5, F. Manso5, M. Marchisone5, S. Porteboeuf-Houssais5, P. Rosnet5, B. Vulpescu5, X. Zhang5, c. Cheshkov6, B. Cheynis6, L. Ducroux6, M. Guilbaud6, R. Tieulent6, A. Uras6
ALICE Collaboration(s)

In this Letter we report the first results on $\pi^\pm$, K$^\pm$, p and pbar production at mid-rapidity (|y|<0.5) in central Pb-Pb collisions at sqrt{s_{NN}} = 2.76 TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at sqrt{s_{NN}} = 200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with sqrt{s_{NN}}, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/pi ratio is in line with predictions from the thermal model, the p/pi ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.
1 :  LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 :  CC IN2P3 - Centre de Calcul de l'inst. national de phy. nucléaire et de phy. des particules
3 :  DRS-IPHC - Département Recherches Subatomiques
4 :  SUBATECH - Laboratoire SUBATECH Nantes
5 :  LPC - Laboratoire de Physique Corpusculaire [Clermont-Ferrand]
6 :  IPNL - Institut de Physique Nucléaire de Lyon
Physique/Physique des Hautes Energies - Expérience

Physique/Physique Nucléaire Expérimentale
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