Charged-Particle Multiplicity Density at Midrapidity in Central Pb-Pb Collisions at sNN=2.76TeV
Abstract
The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair sNN=2.76TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584±4(stat)±76(syst), which corresponds to 8.3±0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at sNN=0.2TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 2010
- DOI:
- 10.1103/PhysRevLett.105.252301
- arXiv:
- arXiv:1011.3916
- Bibcode:
- 2010PhRvL.105y2301A
- Keywords:
-
- 25.75.Ag;
- Global features in relativistic heavy ion collisions;
- Nuclear Experiment
- E-Print:
- 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/3895