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


Adam J., Adamova D., Aggarwal M. M., Rinella G. A., Agnello M., Agrawal N., ...More

JOURNAL OF HIGH ENERGY PHYSICS, vol.2017, no.7, 2017 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 2017 Issue: 7
  • Publication Date: 2017
  • Doi Number: 10.1007/jhep07(2017)052
  • Journal Name: JOURNAL OF HIGH ENERGY PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Heavy Ion Experiments, INDUCED GLUON RADIATION, ENERGY-LOSS, HEAVY-FLAVOR, PLUS, QUARKS, FLOW
  • Bursa Uludag University Affiliated: No

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 < PT < 8 GeV/c in minimum-bias p-Pb collisions at root(NN)-N-S = 5.02 TeV and in 1.3 < PT < 8 GeV/c in the 20% most central Pb-Pb collisions at root(NN)-N-S = 2.76 TeV. The pp reference spectra at root s = 5.02 TeV and root s = 2.76 TeV, needed for the calculation of the nuclear modification factors RpPb and R-PbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at root s = 7 TeV. In the PT interval 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 R-PbPb values increase with large systematic uncertainties. The R-ppb is 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 R-pPb and these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore, the observed reduction of R-PbPb below unity at high PT may be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.