The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1< 8 GeV/c in minimum-bias p-Pb collisions at sNN=5.02 TeV and in 1.3 < pT< 8 GeV/c in the 20% most central Pb-Pb collisions at sNN=2.76 TeV. The pp reference spectra at sNN=5.02 TeV and s=2.76 TeV, needed for the calculation of the nuclear modification factors RpPband RPbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at s=7 TeV. In the pTinterval 3 < pT< 8 GeV/c, a suppression of the yield of electrons from beauty-hadron decays is observed in Pb-Pb compared to pp collisions. Towards lower pT, the RPbPbvalues increase with large systematic uncertainties. The RpPbis consistent with unity within systematic uncertainties and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured RpPband these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore., the observed reduction of RPbPbbelow unity at high pTmay be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.[Figure not available: see fulltext.]

Measurement of electrons from beauty-hadron decays in p-Pb collisions at root(NN)-N-S=5.02 TeV and Pb-Pb collisions at. root(NN)-N-S=2.76 TeV

Barbera, R.;La Rocca, P.;Petta, C.;Riggi, F.;
2017-01-01

Abstract

The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1< 8 GeV/c in minimum-bias p-Pb collisions at sNN=5.02 TeV and in 1.3 < pT< 8 GeV/c in the 20% most central Pb-Pb collisions at sNN=2.76 TeV. The pp reference spectra at sNN=5.02 TeV and s=2.76 TeV, needed for the calculation of the nuclear modification factors RpPband RPbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at s=7 TeV. In the pTinterval 3 < pT< 8 GeV/c, a suppression of the yield of electrons from beauty-hadron decays is observed in Pb-Pb compared to pp collisions. Towards lower pT, the RPbPbvalues increase with large systematic uncertainties. The RpPbis consistent with unity within systematic uncertainties and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured RpPband these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore., the observed reduction of RPbPbbelow unity at high pTmay be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.[Figure not available: see fulltext.]
2017
Heavy Ion Experiments, Nuclear and High Energy Physics.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/317569
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