Measurement of electrons from beauty-hadron decays in pp and Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

TL;DR

This study measures electrons from beauty-hadron decays in proton-proton and Pb-Pb collisions at 5.02 TeV, revealing significant suppression in heavy-ion collisions and comparing results with theoretical models of quark-gluon plasma interactions.

Contribution

First measurement of electrons from beauty-hadron decays in Pb-Pb collisions at this energy, providing insights into heavy quark energy loss in quark-gluon plasma.

Findings

Significant suppression of beauty decay electrons at high pT in Pb-Pb collisions.

No strong pT dependence of suppression above 8 GeV/c within uncertainties.

Results align with models predicting smaller energy loss for beauty quarks.

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 $\sqrt{s_{\rm NN}}$ = 5.02 TeV, using the ALICE detector at the LHC. The cross section measured in pp collisions in the transverse momentum interval $2 < p_{\rm T} < 8$ 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 $2 < p_{\rm T} < 26$ GeV/$c$, was used to compute the nuclear modification factor $R_{\rm AA}$, extrapolating the pp reference cross section to $p_{\rm T}$ larger than 8 GeV/$c$. The measured $R_{\rm AA}$ shows significant suppression of the yield of electrons from beauty-hadron decays at high $p_{\rm T}$ and does not show a significant dependence on $p_{\rm T}$ above 8 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.