Abstract
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN=2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in |n|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6-7 GeV/c and increases significantly at larger pT. The measured suppression of high- pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.
Original language | English |
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Journal | Physics Letters B |
Volume | 696 |
Issue number | 1-2 |
Pages (from-to) | 30-39 |
ISSN | 0370-2693 |
DOIs | |
Publication status | Published - 24 Jan 2011 |