Measurements of Neutral B Decay Branching Fractions to K0S pi+ pi- Final States and the Charge Asymmetry of B0 --> K*+ pi-

Abstract

We analyze the decay B0 -> K0s pi+ pi- using a sample of 232 million Upsilon(4S) -> BB decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. A maximum likelihood fit finds the following branching fractions: BF(B0 -> K0 pi+ pi-) = (43.0 +/- 2.3 +/- 2.3) x 10^{-6}, BF(B0 -> f0 (-> pi+ pi-) K0) = (5.5 +/- 0.7 +/- 0.5 +/- 0.3) x 10^{-6} and BF(B0 -> K*+ pi-) = (11.0 +/- 1.5 +/- 0.5 +/- 0.5) x 10^{-6}. For these results, the first uncertainty is statistical, the second is systematic, and the third (if present) is due to the effect of interference from other resonances. We also measure the CP-violating charge asymmetry in the decay B0 -> K*+ pi-, A(B0 -> K*+ pi-) = -0.11 +/- 0.14 +/- 0.05.