Study of B^{0}→π^{0}π^{0}, B^{±}→π^{±}π^{0}, and B^{±}→K^{±}π^{0} decays, and isospin analysis of B→ππ decays

We present updated measurements of the branching fractions and CP asymmetries for B0→π0π0, B±→π±π0, and B±→K±π0. Based on a sample of 383×106 Υ(4S)→BB̅ decays collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we measure B(B0→π0π0)=(1.47±0.25±0.12)×10-6, B(B±→π±π0)=(5.02±0.46±0.29)×10-6, and B(B±→K±π0)=(13.6±0.6±0.7)×10-6. We also measure the CP asymmetries Cπ0π0=-0.49±0.35±0.05, Aπ±π0=0.03±0.08±0.01, and AK±π0=0.030±0.039±0.010. Finally, we present bounds on the Cabibbo-Kobayashi-Maskawa angle α using isospin relations.