The ALICE measurement of K0S and production at midrapidity in Pb-Pb collisions at ffiffiffiffiffiffiffiffi sNN p ¼ 2:76 TeV is presented. The transverse momentum (pT) spectra are shown for several collision centrality intervals and in the pT range from 0:4 GeV=c (0:6 GeV=c for ) to 12 GeV=c. The pT dependence of the =K0S ratios exhibits maxima in the vicinity of 3 GeV=c, and the positions of the maxima shift towards higher pT with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at ffiffiffis p ¼ 0:9 TeV and at ffiffiffis p ¼ 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured pT spectra above 2 GeV=c progressively decouple from hydrodynamical-model calculations. For higher values of pT, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the pT dependence of the K0S ratio.
|Autori interni:||BRUNO, Giuseppe Eugenio|
|Titolo:||K0S and Λ Production in Pb-Pb Collisions at √s_NN=2.76 TeV|
|Rivista:||PHYSICAL REVIEW LETTERS|
|Data di pubblicazione:||2013|
|Digital Object Identifier (DOI):||10.1103/PhysRevLett.111.222301|
|Appare nelle tipologie:||1.1 Articolo in rivista|