Measurement of B meson production fraction ratios in proton-proton collisions at $\sqrt{s}$ = 13 TeV using open-charm and charmonium decays

Production fractions of B±, B0, and Bs0 mesons are measured in proton-proton collisions at sqrt(s) = 13 TeV using a special data set recorded in 2018 with high-rate triggers designed to collect an unbiased sample of 10^10 b hadrons with the CMS experiment at the LHC. These data made hadronic open-charm decays of B mesons (B(s) -> pi D(s)), where the D meson decays into fully hadronic final states, accessible for this measurement. Production fraction ratios as functions of B meson transverse momentum (pT) and rapidity (y) are measured using the open-charm decays in the kinematic range of 8 < pT < 60 GeV and |y| < 2.25. In addition, the same data are used to measure the relative production fraction ratios on the charmonium decay channels (B(s) -> X J/psi with X being K, K*0(892), phi(102) mesons) with the J/psi meson decaying into a pair of muons. These measurements are normalized in situ to the measured yields in the open-charm channels, thus allowing for the first time to extract the production fractions in charmonium channels directly with an absolute normalization. These results also improve several world-average values of the ratios of branching fractions of B meson decays to charmonium and open-charm states. Finally, we test isospin invariance in B meson production in proton-proton collisions, and observe no significant deviation from isospin invariance within the experimental uncertainties.