Measurement of B meson production fraction ratios in proton-proton collisions at √s = 13 TeV using open-charm and charmonium decays

Production fraction ratios of B⁺, B⁰, and B⁰ₛ mesons are measured in proton-proton collisions at √s = 13 TeV using a special data set recorded in 2018 with high-rate triggers designed to collect an unbiased sample of 10¹⁰ b hadrons with the CMS experiment at the LHC. These data allow the use of the open-charm decays of B mesons (B₍s)→$$π$D₍s)) where the D meson decays into fully hadronic final states. Production fraction ratios as functions of B meson transverse momentum (pT) and rapidity (y) are measured using the open-charm decays in the kinematic range of 8 <p_T< 60 GeV and y<$ 2.25. In addition, the same data are used to measure the relative production fraction ratios with the charmonium decay channels (B$_(s)→ X$\,$J/$ψ$ with X indicating a K⁺, K^*(892)⁰, or $ϕ$(1020) meson) with the J/$ψ$ meson decaying into a pair of muons. By utilizing known branching fractions, precision theoretical calculations, and the open-charm results, the production fraction ratios in the charmonium samples are determined with an absolute normalization for the first time. 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 that it holds within the experimental precision.