Measurement of the branching fractions for B → ωK and B → ωπ

Abstract

We report improved measurements of branching fractions for charmless hadronic two-body B meson decays containing an ω meson in the final state. The results are based on a data sample of 78 fb -1 collected on the Y(4S) resonance by the Belle detector. We measure the branching fractions B(B + → ωK +)=(6.5 -1.2+1.3±0.6) × 10 -6 and B(B +→ωπ +=(5.7 -1.3+1.4±0.6)×10 -6. We give 90% confidence upper limits for B(B 0→ωK 0) ≤7.6×10 -6 and B(B 0→ωπ 0)<1. 9×10 -6. We also obtain the partial rate asymmetries A CP=0.06 -0.18+0.21 ±0.01 for B ±→ωK ± and A CP=0. 50 -0.20+0.23±0.02 for B ±→ωπ ±.