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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.