Bottom quark energy loss and hadronization with B^+ and B⁰ₛ nuclear modification factors using pp and collisions at sNN = 5. 02 TeV

The production cross sections of B⁰ₛ 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 B⁰ₛ J/ (^+^-) (1020) (K^+K^-) and B^+ J/ (^+^-) K^+ decay channels. Results are presented in the transverse momentum (pT) range 7-50 GeV/c and the rapidity interval y 2. 4 for the B mesons. The measured pT-differential cross sections of B^+ and B⁰ₛ 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, RAA, of the B mesons are determined. For pT 10 GeV/c, both mesons are found to be suppressed in PbPb collisions (with RAA values significantly below unity), with less suppression observed for the B⁰ₛ mesons. In this pT range, the RAA values for the B^+ mesons are consistent with those for inclusive charged hadrons and D⁰ mesons. Below 10 GeV/c, both B^+ and B⁰ₛs are found to be less suppressed than either inclusive charged hadrons or D⁰ mesons, with the B⁰ₛ RAA value consistent with unity. The RAA values found for the B^+ and B⁰ₛ 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.