Abstract
We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy collider at the Stanford Linear Accelerator Center. The data sample consists of 29.7 recorded at the resonance and 3.9 off resonance. One of the neutral B mesons, which are produced in pairs at the is fully reconstructed in the CP decay modes and or in flavor-eigenstate modes involving and The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. A neural network tagging algorithm is used to recover events without a clear lepton or kaon tag. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. Wrong-tag probabilities, the time-difference resolution function, and the oscillation frequency are measured with a sample of about 6350 fully-reconstructed decays in hadronic flavor-eigenstate modes. A maximum-likelihood fit to this flavor eigenstate sample finds The value of the asymmetry amplitude is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged decays in the CP-eigenstate modes. We find demonstrating that CP violation exists in the neutral B meson system. We also determine the value of the CP violation parameter which is consistent with the expectation of for no direct CP violation.
- Received 10 January 2002
DOI:https://doi.org/10.1103/PhysRevD.66.032003
©2002 American Physical Society