Measurement of CP Asymmetries and Branching Fractions in Neutral B Meson Decays to Charged Pions and Kaons with the BABAR Detector

This dissertation presents a measurement of CP asymmetries and branching fractions for neutral B meson decays to two-body final states of charged pions and kaons. The results are obtained from a data sample of about 88 million Υ(4S) → B(bar B) decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B factory located at the Stanford Linear Accelerator Center. A fit to kinematic, topological, and particle identification information measures the charge-averaged branching fractions Β(B0 → π+π-) = (4.7 ± 0.6 ± 0.2) x 10-6 and Β(B0 → K+π-) = (17.9 ± 0.9 ± 0.7) x 10-6; the 90% confidence level upper limit Β(B0 → K+K-) < 0.6 x 10-6; and the direct CP-violating charge asymmetry ΑKπ = -0.102 ± 0.050 ± 0.016 [-0.188, -0.016], where the first uncertainties are statistical and the second are systematic and the ranges in square brackets indicate the 90% confidence interval. A fit which adds decay time and b-flavor tagging information measures the CP-violating parameters for B0 → π+π- decays Sππ = 0.02 ± 0.34 ± 0.05 [-0.54, +0.58] and Cππ = -0.30 ± 0.25 ± 0.04 [-0.72, +0.12]