Measurements of the absolute branching fractions of B~+ → X_(cc)K~+ and B~+ → D~((*)0)π~+ at Belle

摘要

We present the measurement of the absolute branching fractions of B~+ → X_(cc)K~+ and B~+ → D~((*)0)π~+ decays, using a data sample of 772 × 10~6 BB pairs collected at the ?(4S) resonance with the Belle detector at the KEKB asymmetric-energy e~+e~? collider. Here, X_(cc) denotes η_c, J/ψ, χ_(c0), χ_(c1), η_c(2S), ψ(2S), ψ(3770), X(3872), and X(3915).We do not observe significant signals for X(3872) or X(3915) and set the 90% confidence level upper limits at B(B~+ → X(3872)K~+) < 2.6 × 10~(?4) and B(B~+ → X(3915)K~+) < 2.8 × 10~(?4). These represent the most stringent upper limit for B(B~+ → X(3872)K~+) to date and the first limit for B(B~+ → X(3915)K~+). The measured branching fractions for η_c and η_c(2S) are the most precise to date, B(B~+ → η_cK~+) = (12.0 ± 0.8 ± 0.7) × 10~(?4) and B(B~+ → η_c(2S)K~+) = (4.8 ± 1.1 ± 0.3) × 10~(?4), where the first and second uncertainties are statistical and systematic, respectively.