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

Abstract

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{sup -1} collected at the {Upsilon}(4S) resonance and 3.9 fb{sup -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/{psi} K{sub s}{sup 0}, {psi}(2S) K{sub s}{sup 0}, {chi}{sub cl} K{sub s}{sup 0}, and J/{psi} K*{sup 0} (822 events); as well as both charged (14304 events) and neutral (10457 events) B decays to flavor-eigenstates including D{sup (*)} and {pi}/{rho}/{alpha}{sub 1}. 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, sin2{beta} = 0.61 {+-} 0.14(stat) {+-} 0.06(syst). These results indicate the existence of indirect CP violation in the B-meson system.