Bottom quark energy loss and hadronization with B⁺ and B<inf>s</inf>⁰ nuclear modification factors using pp and PbPb collisions at √s<inf>NN</inf> = 5.02 TeV

Abstract

The production cross sections of B<inf>s</inf>⁰ and B⁺ mesons are reported in proton-proton (pp) collisions recorded by the CMS experiment at the CERN LHC with a center-of-mass energy of 5.02 TeV. The data sample corresponds to an integrated luminosity of 302 pb⁻¹. The cross sections are based on measurements of the B<inf>s</inf>⁰ → J/ψ(μ⁺μ⁻)ϕ(1020)(K⁺K⁻) and B⁺→ J/ψ(μ⁺μ⁻)K⁺ decay channels. Results are presented in the transverse momentum (p<inf>T</inf>) range 7–50 GeV/c and the rapidity interval |y| < 2.4 for the B mesons. The measured p<inf>T</inf>-differential cross sections of B⁺ and B<inf>s</inf>⁰ in pp collisions are well described by fixed-order plus next-to-leading logarithm perturbative quantum chromodynamics calculations. Using previous PbPb collision measurements at the same nucleon-nucleon center-of-mass energy, the nuclear modification factors, R<inf>AA</inf>, of the B mesons are determined. For p<inf>T</inf>> 10 GeV/c, both mesons are found to be suppressed in PbPb collisions (with R<inf>AA</inf> values significantly below unity), with less suppression observed for the Bs0 mesons. In this p<inf>T</inf> range, the R<inf>AA</inf> values for the B⁺ mesons are consistent with those for inclusive charged hadrons and D⁰ mesons. Below 10 GeV/c, both B⁺ and Bs0 are found to be less suppressed than either inclusive charged hadrons or D⁰ mesons, with the Bs0R<inf>AA</inf> value consistent with unity. The R<inf>AA</inf> values found for the B⁺ and Bs0 are compared to theoretical calculations, providing constraints on the mechanism of bottom quark energy loss and hadronization in the quark-gluon plasma, the hot and dense matter created in ultrarelativistic heavy ion collisions.