Measurement of electrons from beauty-hadron decays in pp and Pb-Pb collisions at sNN =5.02 TeV

Abstract

The production of electrons from beauty-hadron decays was measured at midrapidity in proton-proton ($pp$) and central Pb-Pb collisions at center-of-mass energy per nucleon-nucleon pair $\sqrt{{s}_{NN}}$ = 5.02 TeV, using the ALICE detector at the LHC. The cross section measured in $pp$ collisions in the transverse momentum interval $2<{p}_{\mathrm{T}}<8\phantom{\rule{0.16em}{0ex}}\mathrm{GeV}/c$ was compared with models based on perturbative quantum chromodynamics calculations. The yield in the 10% most central Pb-Pb collisions, measured in the interval $2<{p}_{\mathrm{T}}<26\phantom{\rule{0.16em}{0ex}}\mathrm{GeV}/c$, was used to compute the nuclear modification factor ${R}_{AA}$, extrapolating the $pp$ reference cross section to ${p}_{\mathrm{T}}$ larger than 8 $\mathrm{GeV}/c$. The measured ${R}_{AA}$ shows significant suppression of the yield of electrons from beauty-hadron decays at high ${p}_{\mathrm{T}}$ and does not show a significant dependence above $8\phantom{\rule{0.16em}{0ex}}\mathrm{GeV}/c$ within uncertainties. The results are described by several theoretical models based on different implementations of the interaction of heavy quarks with a quark-gluon plasma, which predict a smaller energy loss for beauty quarks compared to light and charm quarks.