Measurement of the CP-violating Asymmetries in B0 -> KS pi0 and of the Branching Fraction of B0 -> K0 pi0

Abstract

We present a measurement of the time-dependent CP-violating asymmetries in B0 -> K0S pi0 decays based on 348 million Y(4S) -> BBbar events collected by the BABAR experiment at the PEP-II asymmetric-energy B Factory at SLAC. We measure the direct CP-violating asymmetry C_{K0S pi0} = 0.20 +/- 0.16 +/- 0.03 and the CP-violating asymmetry in the interference between mixing and decay S_{K0S pi0} = 0.33 +/- 0.26 +/- 0.04 where the first error is statistical and the second systematic. On the same sample, we measure the decay branching fraction, obtaining B(B0 -> K0S pi0)= (10.5 +/- 0.7 +/- 0.5) 10^{-6}. All results presented here are preliminary.