The multi-strange baryon yields in Pb-Pb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, Xi and Omega production rates have been measured with the ALICE experiment as a function of transverse momentum, p(T), 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 < p(T) < 7.2 GeV/c and 0.8 GeV/c < p(T) < 5 GeV/c, for E and S-2 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 p(T) spectra are analysed as a function of event charged -particle multiplicity, which in p-Pb collisions ranges over one order of magnitude and lies between those observed in pp and Pb-Pb collisions. The measured p -r 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.

Multi-strange baryon production in p-Pb collisions at root(NN)-N-S=5.02 TeV

CASULA, ESTER ANNA RITA;Cicalo, C.;DE FALCO, ALESSANDRO;FIONDA, FIORELLA MARIA CELESTE;INCANI, ELISA;USAI, GIANLUCA;
2016-01-01

Abstract

The multi-strange baryon yields in Pb-Pb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, Xi and Omega production rates have been measured with the ALICE experiment as a function of transverse momentum, p(T), 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 < p(T) < 7.2 GeV/c and 0.8 GeV/c < p(T) < 5 GeV/c, for E and S-2 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 p(T) spectra are analysed as a function of event charged -particle multiplicity, which in p-Pb collisions ranges over one order of magnitude and lies between those observed in pp and Pb-Pb collisions. The measured p -r 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.
2016
Proton-proton collisions; Quark-gluon plasma; Energy-dependance; Root-S=7 TEV; Mid-rapidity; Enhancement; ALICE; GEV/C; Kaon; Pion
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/189161
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