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

In this Letter we report the first results on pi, K, p, production at midrapidity (jyj < 0:5) in central Pb-Pb collisions at sNN= 2.76 TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at sNN= 200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with fsNN= 2.76, 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.