Observation of ${B}^{0}$ Meson Decay to ${a}_{1}^{\ifmmode\pm\else\textpm\fi{}}(1260){\ensuremath{\pi}}^{\ensuremath{\mp}}$

Observation of $B^{0}$ Meson Decay to $a_{1}^{\pm} (1260) π^{\mp}$

B. Aubert et al. (BABAR Collaboration)

Phys. Rev. Lett. 97, 051802 – Published 4 August 2006

Abstract

We present a measurement of the branching fraction of the decay $B^{0} \to a_{1}^{\pm} (1260) π^{\mp}$ with $a_{1}^{\pm} (1260) \to π^{\mp} π^{\pm} π^{\pm}$ . The data sample corresponds to $218 \times 10^{6}$ $B \bar{B}$ pairs produced in $e^{+} e^{-}$ annihilation through the $Υ (4 S)$ resonance. We measure the branching fraction $B (B^{0} \to a_{1}^{\pm} (1260) π^{\mp}) B (a_{1}^{\pm} (1260) \to π^{\mp} π^{\pm} π^{\pm}) = (16.6 \pm 1.9 \pm 1.5) \times 10^{- 6}$ , where the first error quoted is statistical and the second is systematic.