| In this dissertation, a measurement of CP-violating effects in decays of neutral B meson is presented. The data sample for this measurement consists of about 88 million Upsilon(4S) → BB¯ decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy e +e- collider, located at the Stanford Linear Accelerator Center. One neutral B meson is fully reconstructed in the CP eigenstates J/psi K0S , psi(25) K0S , chic1 K0S , and etac K0S , or in the flavor eigenstates D(*)- pi+/rho+/ a+1 and J/psiK*0 ( K*0 → K+pi -). The other B meson is determined to be either a B0 or a B¯ 0, at the time of its decay, from the properties of its decay products. The proper time Deltat elapsed between the decay of the two mesons is determined by reconstructing their decay vertices, and by measuring the distance between them. The CP asymmetry amplitude sin2beta is determined by the distributions of Deltat in events with a reconstructed B meson in CP eigenstates. The detector resolution and the b-flavor-tagging parameters are constrained by the Deltat distributions of events with a fully reconstructed flavor eigenstate. From a simultaneous maximum-likelihood fit to the Deltat distributions of all selected events in CP and flavor eigenstates, the value of sin2beta is measured to be 0.755 +/- 0.074 (stat) +/- 0.030 (syst). This value is in agreement with the Standard Model prediction, and represents a successful test of the Kobayashi-Maskawa mechanism of CP violation. |
