The production cross sections of Bs 0 mesons and charge conjugates are measured in proton-proton (pp) and PbPb collisions via the exclusive decay channel Bs 0→J/ψϕ→μ+μ−K+K− at a center-of-mass energy of 5.02 TeV per nucleon pair and within the rapidity range |y|<2.4 using the CMS detector at the LHC. The pp measurement is performed as a function of transverse momentum (pT) of the Bs 0 mesons in the range of 7 to 50 GeV/c and is compared to the predictions of perturbative QCD calculations. The Bs 0 production yield in PbPb collisions is measured in two pT intervals, 7 to 15 and 15 to 50 GeV/c, and compared to the yield in pp collisions in the same kinematic region. The nuclear modification factor (RAA) is found to be 1.5±0.6(stat)±0.5(syst) for 7–15 GeV/c, and 0.87±0.30(stat)±0.17(syst) for 15–50 GeV/c, respectively. Within current uncertainties, the Bs 0 results are consistent with models of strangeness enhancement, and suppression by parton energy loss, as observed for the B+ mesons.
|Журнал||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Состояние||Опубликовано - 10 сен 2019|