A Study of Factorization and a Measurement of CP Violation

We report on a study of the decay {bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -} with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million B{sup 0}{bar B}{sup 0} decays collected between 1999 and 2004, we measure the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -}) = (2.88 {+-} 0.21(stat.) {+-} 0.31(syst.)) x 10{sup -3}. We study the invariant mass spectrum of the {omega}{pi}{sup -} system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in {tau}{sup -} {yields} {omega}{pi}{sup -} {nu}{sub {tau}}. We also measure the polarization of the D*{sup +} as a function of the {omega}{pi}{sup -} mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*{sup +} to be {Lambda}{sub L}/{Lambda} = 0.654 {+-} 0.042(stat.) {+-} 0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as {bar B}{sup 0} {yields} D*{sup +} {rho}(1450){sup -}, {rho}(1450){sup -} {yields} {omega}{pi}{sup -}. Furthermore, we present the results on the time-dependent CP asymmetry in neutral B meson decays tomore » the CP eigenstate J/{psi}K{sub L}. The measurements use a data sample of about 88 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2002 with the BABAR detector. We study events in which one neutral B meson is fully reconstructed in the J/{psi}K{sub L} final state and the other B meson is determined to be either a B{sup 0} or a {bar B}{sup 0} from its decay products. The amplitude of the CP asymmetry, which in the Standard Model is proportional to sin 2{beta}, is derived from the decay-time distributions in such events. We measure sin 2{beta} = 0.723 {+-} 0.158(stat.) {+-} 0.086(syst.), which is consistent with Standard Model expectations.« less