The ALICE measurement of K-S(0) and Lambda production at midrapidity in Pb-Pb collisions at root sNN = 2.76 TeV is presented. The transverse momentum (p(T)) spectra are shown for several collision centrality intervals and in the p(T) range from 0: 4 GeV/c (0: 6 GeV/c for Lambda) to 12 GeV/c. The p(T) dependence of the Lambda/K-S(0) ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher p(T) 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 p(T) is not observed in pp interactions at root s = 0.9 TeV and at root s = 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured p(T) spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of p(T), models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the p(T) dependence of the Lambda/K-S(0) ratio.

K-S(0) and Lambda Production in Pb-Pb Collisions at root s(NN)=2: 76 TeV / Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri, G.; Agnello, Michelangelo; Agocs, A. G.; Agostinelli, A.; Ahammed, Z.; Ahmad, N.; Ahmad, A.; Ahn, S. A.; Ahn, S. U.; Ahmed, I.; Aimo, Ilaria; Ajaz, M.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Aguelov, V.; Anielski, J.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Bufalino, Stefania. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 111:22(2013), pp. 1-10. [10.1103/PhysRevLett.111.222301]

K-S(0) and Lambda Production in Pb-Pb Collisions at root s(NN)=2: 76 TeV

AGNELLO, MICHELANGELO;AIMO, ILARIA;BUFALINO, STEFANIA
2013

Abstract

The ALICE measurement of K-S(0) and Lambda production at midrapidity in Pb-Pb collisions at root sNN = 2.76 TeV is presented. The transverse momentum (p(T)) spectra are shown for several collision centrality intervals and in the p(T) range from 0: 4 GeV/c (0: 6 GeV/c for Lambda) to 12 GeV/c. The p(T) dependence of the Lambda/K-S(0) ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher p(T) 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 p(T) is not observed in pp interactions at root s = 0.9 TeV and at root s = 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured p(T) spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of p(T), models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the p(T) dependence of the Lambda/K-S(0) ratio.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2534495
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