Multi-strange baryon production in p-Pb collisions at √sNN = 5.02 TeV
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Colleges, School and Institutes
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, pT, in p-Pb collisions at a centre-of-mass energy of √sNN = 5.02 TeV. The results cover the kinematic ranges 0.6 GeV/c < pT < 7.2 GeV/c and 0.8 GeV/c < pT < 5 GeV/c , for Ξ and Ω respectively, in the common rapidity interval − 0.5 < yCMS < 0 . Multi-strange baryons have been identified by reconstructing their weak decays into charged particles. The pT 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 Pb-Pb collisions. The measured pT 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 p-Pb collisions. The yield of hyperons relative to charged pions is studied and compared with results from pp and Pb-Pb collisions. A continuous increase in the yield ratios as a function of multiplicity is observed in p-Pb data, the values of which range from those measured in minimum bias pp to the ones in Pb-Pb 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.
|Number of pages||13|
|Journal||Physics Letters B|
|Early online date||12 May 2016|
|Publication status||Published - 10 Jul 2016|