KS0 and Λ production in Pb-Pb collisions at √s NN=2.76 TeV


Abelev B., Adam J., Adamová D., Adare A., Aggarwal M., Aglieri Rinella G., ...More

Physical Review Letters, vol.111, no.22, 2013 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 111 Issue: 22
  • Publication Date: 2013
  • Doi Number: 10.1103/physrevlett.111.222301
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Yıldız Technical University Affiliated: No

Abstract

The ALICE measurement of KS0 and Λ 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 0.4 GeV/c (0.6 GeV/c for Λ) to 12 GeV/c. The pT dependence of the Λ/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 p T dependence of the Λ/KS0 ratio. © 2013 CERN.