Measurement of the Branching Fraction of Y(4S) to Neutral B Pairs

We measure a model independent measurement of the branching fraction of Upsilon(4S) to neutral B pairs. We use a sample of 476 million B-meson anti-B-meson pairs collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B-Factory at SLAC National Accelerator Laboratory. The B mesons are reconstructed through the channel of anti-B0 decays to D*+ lepton anti-neutrino using a partial reconstruction method. Our result does not depend on any branching fraction, the reconstruction efficiency, and the ratio of the charged and neutral B meson. This measurement is an important input for normalizing many B mesons decay.