Improved measurements of branching fractions and CP partial rate asymmetries for B ->omega K and B ->omega pi

Abstract

We report improved measurements of B to pseudoscalar-vector decays containing an ω meson in the final state. Our results are obtained from a data sample that contains 388×106 BB̄ pairs accumulated at the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We measure the following branching fractions: B(B+→ωK+)= [8.1±0.6(stat.)±0.6(syst.)]×10-6, B(B+→ωπ+)= [6.9±0.6(stat.)±0.5(syst.)]×10-6, and B(B0→ωK0)= [4.4-0.7+0.8(stat.)±0.4(syst.)]×10-6. The partial width ratio Γ(B+→ωK+)Γ(B0→ωK0)=1.7±0.3(stat.) ±0.1(sys.). We also set the 90% confidence level upper limit B(B0→ωπ0)<2.0×10-6. In addition, we obtain the partial rate asymmetries ACP=0.05-0.07+0.08(stat.)±0.01..