Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at sNN=2.76TeV
Abstract
In this Letter we report the first results on π±, K±, p, and p¯ 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.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 2012
- DOI:
- 10.1103/PhysRevLett.109.252301
- arXiv:
- arXiv:1208.1974
- Bibcode:
- 2012PhRvL.109y2301A
- Keywords:
-
- 25.75.Dw;
- 24.10.Nz;
- 25.75.Ag;
- Particle and resonance production;
- Hydrodynamic models;
- Global features in relativistic heavy ion collisions;
- High Energy Physics - Experiment;
- Nuclear Experiment
- E-Print:
- 15 pages, 2 captioned figures, 1 table, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/2869