ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2006, vol. 97, p. -
Observation of B0 meson decay to a1±(1260)π
We present a measurement of the branching fraction of the decay B0→a1±(1260)π with a1±(1260) →ππ±π±. The data sample corresponds to 218×106 BB̄ pairs produced in e+e- annihilation through the Υ(4S) resonance. We measure the branching fraction B(B0→a1±(1260)π) B(a1±(1260)→ππ±π±)=(16.6±1.9±1. 5)×10-6, where the first error quoted is statistical and the second is systematic. © 2006 The American Physical Society.