Observation of B+- -> omega K+- Decay

Abstract

We report the first observation of the charmless two-body mode $B^{\pm }\to \omega K^{\pm }$ decay, and a new measurement of the branching fraction for the $B^{\pm }\to \omega {\pi }^{\pm }$ decay. The measured branching fractions are $\mathcal{B}(B^{\pm }\to \omega K^{\pm })=(9.2{}_{-2.3}^{+2.6}\pm 1.0)\times 10^{-6}$ and $\mathcal{B}(B^{\pm }\to \omega {\pi }^{\pm })=(4.2{}_{-1.8}^{+2.0}\pm 0.5)\times 10^{-6}$. %and we set 90% confidence level upper limits of %$\mathcal{B}(B^{-}\to \omega {\pi }^{-})<8.1\times 10^{-6}$. We also measure the partial rate asymmetry of $B^{\pm }\to \omega K^{\pm }$ decays and obtain ${\mathcal{A}}_{CP}=-0.21\pm 0.28\pm 0.03$. The results are based on a data sample of 29.4 fb${}^{-1}$ collected on the ${\rm Y}(4S)$ resonance by the Belle detector at the KEKB $e^{+}{e}^{-}$ collider.

5 pages, 4 figures, resubmitted to Phys. Rev. Lett