Measurements of Branching Fractions and Direct CP Asymmetries in pi^+ pi^0, K^+ pi^0 and K^0 pi^0 B Decays

Abstract

We present preliminary results of the analyses of B^+ --> h^+ pi^0 (with h^+ = pi^+, K^+) and B^0 --> K^0 pi^0 decays from a sample of approximately 88 million B bar{B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure the pi^+ pi^0 branching fraction and we obtain B(B^+ --> pi^+ pi^0) = (5.5^{+1.0}_{-0.9} +/- 0.6) times 10^{-6} with a significance of 7.7 sigma including systematic uncertainties. We measure the K^+ pi^0 and K^0 pi^0 branching fractions to be B(B^+ --> K^+ pi^0) = (12.8^{+1.2}_{-1.1} +/- 1.0) times 10^{-6} and B(B^0 --> K^0 pi^0) = (10.4 +/- 1.5 +/- 0.8) times 10^{-6}. At the same time, the direct CP-violating asymmetries are investigated and we find A_{pi^+ pi^0} = -0.03_{-0.17}^{+0.18} +/- 0.02, A_{K^+ pi^0} = -0.09 +/- 0.09 +/- 0.01 and A_{K^0 pi^0} = 0.03 +/- 0.36 +/- 0.09, where the errors are statistical and systematic, respectively.