Study of B(0)->pi(0)pi(0), B(+/-)->pi(+/-)pi(0), and B(+/-)-> K(+/-)pi(0) decays, and isospin analysis of B ->pi pi decays

We present updated measurements of the branching fractions and CP asymmetries for B-0 ->pi(0)pi(0), B-+/-->pi(+/-)pi(0), and B-+/--> K-+/-pi(0). Based on a sample of 383x10(6) Upsilon(4S)-> B (B) over bar decays collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we measure B(B-0 ->pi(0)pi(0))=(1.47 +/- 0.25 +/- 0.12)x10(-6), B(B-+/-->pi(+/-)pi(0))=(5.02 +/- 0.46 +/- 0.29)x10(-6), and B(B-+/--> K-+/-pi(0))=(13.6 +/- 0.6 +/- 0.7)x10(-6). We also measure the CP asymmetries C-pi(pi)0(0)=-0.49 +/- 0.35 +/- 0.05, A(pi)(pi)(+)(0)=0.03 +/- 0.08 +/- 0.01, and A(K)(pi)(+)(0)=0.030 +/- 0.039 +/- 0.010. Finally, we present bounds on the Cabibbo-Kobayashi-Maskawa angle alpha using isospin relations.