Measurement of the B±→ρ±π0 branching fraction and direct CP asymmetry

We present improved measurements of the branching fraction and CP asymmetry for the process B±→ρ±π0. The data sample corresponding to 211  fb-1 comprises 232×106 Υ(4S)→BB̅ decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The yield and CP asymmetry are measured using an extended maximum likelihood fitting method. The branching fraction and CP asymmetry are found to be B(B±→ρ±π0)=[10.2±1.4(stat)±0.9(syst)]×10-6 and ACP(B±→ρ±π0)=-0.01±0.13(stat)±0.02(syst).