Inclusive decays of B-meson to J/ψ and χ c1 using \(\boldsymbol {386\times 10^{6} B\bar {B}}\) events

The inclusive decays of B-mesons to charmonium have been studied in a data sample of 386 million \(B\bar {B}\) events. The data sample has been collected by the Belle detector at the KEKB asymmetric energy e + e − collider operating at the Υ(4S) resonance. The branching fractions have been measured for the inclusive decays to J/ψ + X and χ c1 + X. The measured branching fraction for J/ψ + X is \(\mathcal {B}(B \to J/\psi (\to e^{+}e^{-})+X) = (1.10\pm 0.005\pm 0.057)\%\) and \(\mathcal {B}(B\to J/\psi (\to \mu ^{+}\mu ^{-})+X) = (1.08\pm 0.004\pm 0.056)\%\), while the inclusive χ c1 + X branching fraction is found to be \(\mathcal {B}(B\to \chi _{c1}+X) = (0.44\pm 0.01\pm 0.06)\%\). The feed-down contribution from higher charmonium states is subtracted from the measured branching fractions and the direct branching fractions are obtained to be \(\mathcal {B}(B\to J/\psi +X) = (0.77\pm 0.04\pm 0.06)\%\) and \(\mathcal {B}(B \to \chi _{c1}+X) = (0.41\pm 0.01\pm 0.06)\%.\)