Observation of B Meson Decays to b1π and b1K

Abstract

We present the results of searches for decays of B mesons to final states with a b 1 meson and a charged pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 382 × 10 6 B ¯¯¯ B pairs produced in e + e − annihilation. The results for the branching fractions are, in units of 10 − 6 , B ( B + → b 0 1 π + ) = 6.7 ± 1.7 ± 1.0 , B ( B + → b 0 1 K + ) = 9.1 ± 1.7 ± 1.0 , B ( B 0 → b ∓ 1 π ± ) = 10.9 ± 1.2 ± 0.9 , and B ( B 0 → b − 1 K + ) = 7.4 ± 1.0 ± 1.0 , with the assumption that B ( b 1 → ω π ) = 1 . We also measure charge and flavor asymmetries A ch ( B + → b 0 1 π + ) = 0.05 ± 0.16 ± 0.02 , A ch ( B + → b 0 1 K + ) = − 0.46 ± 0.20 ± 0.02 , A ch ( B 0 → b ∓ 1 π ± ) = − 0.05 ± 0.10 ± 0.02 , C ( B 0 → b ∓ 1 π ± ) = − 0.22 ± 0.23 ± 0.05 , Δ C ( B 0 → b ∓ 1 π ± ) = − 1.04 ± 0.23 ± 0.08 , and A ch ( B 0 → b − 1 K + ) = − 0.07 ± 0.12 ± 0.02 . The first error quoted is statistical, and the second systematic.