The ALICE measurement of KS0 and Lambda production at midrapidity in Pb-Pb collisions at √sNN=2.76 TeV is presented. The transverse momentum (pT ) spectra are shown for several collision centrality intervals and in the pT range from 0.4GeV/c (0.6 GeV/c for Lambda) to 12 GeV/c. The pT dependence of the Lambda/KS0 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 √s=0.9 TeV and at √s=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 Lambda/KS0 ratio.
Titolo: | K0S and Lambda Production in Pb-Pb Collisions at √sNN=2.76 TeV | |
Autori: | ||
Data di pubblicazione: | 2013 | |
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Abstract: | The ALICE measurement of KS0 and Lambda production at midrapidity in Pb-Pb collisions at √sNN=2.76 TeV is presented. The transverse momentum (pT ) spectra are shown for several collision centrality intervals and in the pT range from 0.4GeV/c (0.6 GeV/c for Lambda) to 12 GeV/c. The pT dependence of the Lambda/KS0 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 √s=0.9 TeV and at √s=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 Lambda/KS0 ratio. | |
Handle: | http://hdl.handle.net/11386/4255479 | |
Appare nelle tipologie: | 1.1.1 Articolo su rivista con DOI |