Multi-strange baryon production in p Pb collisions at
The multi-strange baryon yields in PbPb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, Ξ and Ω production rates have been measured with the ALICE experiment as a function of transverse momentum, p T , in pPb collisions at a centre-of-mass energy of √sNN=5.02 TeV. The results cover the kinematic ranges 0.6 GeV/c < p T < 7.2 GeV/c and 0.8 GeV/c < p T < 5 GeV/c, for Ξ and Ω respectively, in the common rapidity interval -0.5 < y CMS < 0. Multi-strange baryons have been identified by reconstructing their weak decays into charged particles. The p T spectra are analysed as a function of event charged-particle multiplicity, which in pPb collisions ranges over one order of magnitude and lies between those observed in pp and PbPb collisions. The measured p T distributions are compared to the expectations from a Blast-Wave model. The parameters which describe the production of lighter hadron species also describe the hyperon spectra in high multiplicity pPb collisions. The yield of hyperons relative to charged pions is studied and compared with results from pp and PbPb collisions. A continuous increase in the yield ratios as a function of multiplicity is observed in pPb data, the values of which range from those measured in minimum bias pp to the ones in PbPb collisions. A statistical model qualitatively describes this multiplicity dependence using a canonical suppression mechanism, in which the small volume causes a relative reduction of hadron production dependent on the strangeness content of the hyperon.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Contributing Organization:
- ALICE Collaboration
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1253203
- Alternate ID(s):
- OSTI ID: 1379508
- Journal Information:
- Physics Letters B, Journal Name: Physics Letters B Vol. 758 Journal Issue: C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
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