Evidence for Charged B Meson Decays to a±1(1260)π0 and a01(1260)π±

We present measurements of the branching fractions for the decays B ± → a ± 1 ( 1260 ) π 0 and B ± → a 0 1 ( 1260 ) π ± from a data sample of 232 × 10 6 B ¯¯¯ B pairs produced in e + e − annihilation through the Υ ( 4 S ) resonance. We measure the branching fraction B ( B ± → a ± 1 ( 1260 ) π 0 ) × B ( a ± 1 ( 1260 ) → π − π + π ± ) = ( 13.2 ± 2.7 ± 2.1 ) × 10 − 6 with a significance of 4.2 σ , and the branching fraction B ( B ± → a 0 1 ( 1260 ) π ± ) × B ( a 0 1 ( 1260 ) → π − π + π 0 ) = ( 20.4 ± 4.7 ± 3.4 ) × 10 − 6 with a significance of 3.8 σ , where the first error quoted is statistical and the second is systematic