A Measurement of the CP Parameter sine two beta Using Fully Reconstructed B to ccbar Decays at the BABAR Experiment

This dissertation presents a measurement of the time-dependent CP-violating asymmetries in the neutral B-meson system performed with data collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The data sample used consists of 29.7 fb-1 collected at the Υ(4S) resonance and 3.9 fb-1 collected off-resonance. We analyze three samples of fully-reconstructed B-meson decays: a sample of decays to CP eigenstates in the modes J/ψ Ks0, ψ(2S) Ks0, χcl Ks0, and J/ψ K*0 (822 events); as well as both charged (14304 events) and neutral (10457 events) B decays to flavor-eigenstates including D(*) and π/ρ/α1. In all cases, the proper decay time difference between the reconstructed B-meson and the recoiling B-meson is determined by measuring the separation of the two decay vertices. Furthermore, the flavor of the recoiling B-meson is tagged using a neural network algorithm. We use the flavor-eigenstate samples to calibrate both the vertexing and tagging performance. We measure the amplitude of the CP asymmetry, sin2β = 0.61 ± 0.14(stat) ± 0.06(syst). These results indicate the existence of indirect CP violation in the B-meson system