Search for rare decays $B^{+} \to D_{s}^{(\ast)+}\eta$, $D_{s}^{(\ast)+}\bar{K}^{0}$, $D^{+}\eta$, and $D^{+}K^{0}$

TL;DR

This study searches for rare B+ meson decays into specific D_s and D mesons with neutral mesons, setting upper limits on their branching fractions due to no observed evidence, and also reports improved measurements of certain color-suppressed decay modes.

Contribution

The paper provides the first upper limits on several rare decay modes of B+ mesons and improves measurements of specific color-suppressed decay branching fractions.

Findings

No evidence found for the rare decay modes.

Upper limits set on branching fractions at 90% confidence level.

Improved measurements of (^{0}ta) and (^{0}ar{K}^{0})

Abstract

We present a study of rare decay modes $B^{+} \to D_{s}^{+}h^{0}$, $B^{+} \to D_{s}^{\ast+}h^{0}$, and $B^{+} \to D^{+}h^{0}$, where $h^{0}$ denotes the neutral mesons $\eta$ or $K^{0}$, using a data sample of $(772 \pm 10 ) \times 10^{6}$ $B\bar{B}$ events produced at the $\Upsilon(4S)$ resonance. The data were collected by the Belle detector operating at the asymmetric-energy KEKB collider. We observe no evidence for these decays, so we provide upper limits at the 90$\%$ confidence level on the branching fractions of $B^{+} \to D_{s}^{+}h^{0}$, $D_{s}^{\ast+}h^{0}$, and $D^{+}h^{0}$ decay modes. Along with rare decay modes, we report improved measurements of the color-suppressed decay branching fractions $\mathcal{B}(\bar{B}^{0} \to D^{0}\eta)$ = (26.6 $\pm$ 1.2 $\pm$ 2.1) $\times$ $10^{-5}$ and $\mathcal{B}(\bar{B}^{0} \to D^{0}\bar{K}^{0})$ = (5.6 $\pm$ 0.5 $\pm$ 0.2) $\times$ $10^{-5}$. The first and second uncertainties are statistical and systematic, respectively.