Improved measurements of branching fractions andCPpartial rate asymmetries forB→ωKandB→ωπ
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Abstract
We report improved measurements of $B$ to pseudoscalar-vector decays containing an $\ensuremath{\omega}$ meson in the final state. Our results are obtained from a data sample that contains $388\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs accumulated at the $\ensuremath{\Upsilon}(4S)$ resonance, with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We measure the following branching fractions: $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\omega}{K}^{+})=[8.1\ifmmode\pm\else\textpm\fi{}0.6(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.6(\mathrm{syst}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{+})=[6.9\ifmmode\pm\else\textpm\fi{}0.6(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.5(\mathrm{syst}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, and $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}\ensuremath{\omega}{K}^{0})=[{4.4}_{\ensuremath{-}0.7}^{+0.8}(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{syst}.)]\ifmmode\times\else\texttimes\fi{}\phantom{\rule{0ex}{0ex}}{10}^{\ensuremath{-}6}$. The partial width ratio $\frac{\ensuremath{\Gamma}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\omega}{K}^{+})}{\ensuremath{\Gamma}({B}^{0}\ensuremath{\rightarrow}\ensuremath{\omega}{K}^{0})}=1.7\ifmmode\pm\else\textpm\fi{}0.3(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.1(\mathrm{sys}.)$. We also set the 90% confidence level upper limit $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0})<2.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. In addition, we obtain the partial rate asymmetries ${\mathcal{A}}_{CP}={0.05}_{\ensuremath{-}0.07}^{+0.08}(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.01(\mathrm{syst}.)$ for ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\omega}{K}^{+}$, and ${\mathcal{A}}_{CP}=\ensuremath{-}0.02\ifmmode\pm\else\textpm\fi{}0.09(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.01(\mathrm{syst}.)$ for ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{+}$.