17 research outputs found

    Measurement of the B-Meson Inclusive Semileptonic Branching Fraction and Electron-Energy Moments

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    We report a new measurement of the B-meson semileptonic decay momentum spectrum that has been made with a sample of 9.4/fb of electron-positron annihilation data collected with the CLEO II detector at the Y(4S) resonance. Electrons from primary semileptonic decays and secondary charm decays were separated by using charge and angular correlations in Y(4S) events with a high-momentum lepton and an additional electron. We determined the semileptonic branching fraction to be (10.91 +- 0.09 +- 0.24)% from the normalization of the electron-energy spectrum. We also measured the moments of the electron energy spectrum with minimum energies from 0.6 GeV to 1.5 GeV.Comment: 36 pages postscript, als available through http://w4.lns.cornell.edu/public/CLNS/, Submitted to PRD (back-to-back with preceding preprint hep-ex/0403052

    Measurements of the Branching Fractions and Helicity Amplitudes in B --> D* rho Decays

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    Using 9.1 fb-1 of e+ e- data collected at the Upsilon(4S) with the CLEO detector using the Cornell Electron Storage Ring, measurements are reported for both the branching fractions and the helicity amplitudes for the decays B- -> D*0 rho- and B0bar -> D*+ rho-. The fraction of longitudinal polarization in B0bar -> D*+ rho- is found to be consistent with that in B0bar -> D*+ l- nubar at q^2 = M^2_rho, indicating that the factorization approximation works well. The longitudinal polarization in the B- mode is similar. The measurements also show evidence of non-trivial final-state interaction phases for the helicity amplitudes.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

    Cabibbo-Suppressed Decays of D^+ \to \pi^+\pi^0, K^+\bar{K}^0, K^+\pi^0

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    Using a 13.7 fb-1 data sample collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D+ meson: BR(D+ -> pi+ pi0) = (1.31 +/- 0.17 +/- 0.09 +/- 0.09) x 10^(-3)and BR(D+ -> K+ K0bar) = (5.24 +/- 0.43 +/- 0.20 +/- 0.34) x 10^(-3) which are significant improvements over past measurements. The errors reflect statistical and systematical uncertainties as well as the uncertainty in the absolute D+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode BR(D+ -> K+ pi0) < 4.2 x 10^(-4).Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

    Correlated inclusive /\bar production in e+e- annihilations at sqrt(s)~10.5 GeV

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    Using a 13.7/fb sample of continuum two-jet e+e- -> qqbar events collected with the CLEO detector, we have searched for correlations between / and /\bar particles, specifically in cases where the opening angle between the two particles is large and each has momentum >>1 GeV/c. Such correlations may indicate the presence of baryon number conservation at the primary quark level. A previous CLEO study of /\c/\cbar correlations indicated direct, associated production of primary charmed baryons /\c: e+e- -> ccbar -> /\c/\cbar. That effect was not observed in Monte Carlo simulations. Our current search for similar direct, associated production of / baryons at the primary quark level (e+e- -> ssbar -> /\bar, e.g.) qualitatively indicates a similar effect, although it relies on a Monte Carlo dependent subtraction of background /\bar production (based on the default JETSET 7.4 event generator)

    Studies of the Cabbibo-Suppressed Decays D+π0+νD^+ \to \pi^0 \ell^+ \nu and D+ηe+νeD^+ \to \eta e^+ \nu_e

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    Using 4.8 fb1^{-1} of data taken with the CLEO II detector, the branching fraction for the Cabibbo-suppressed decay D+π0+νD^+\to\pi^0\ell^+\nu measured relative to the Cabibbo favored decay D+K0ˉ+νD^+\to\bar{K^0}\ell^+\nu is found to be 0.046±0.014±0.0170.046\pm 0.014\pm 0.017. Using VcsV_{cs} and VcdV_{cd} from unitarity constraints, we determine f+π(0)/f+K(0)2=0.9±0.3±0.3| f_+^{\pi}(0)/f_+^K(0)|^2=0.9\pm 0.3\pm 0.3 We also present a 90% confidence level upper limit for the branching ratio of the decay D+ηe+νeD^+ \to \eta e^+\nu_e relative to that for D+π0e+νeD^+ \to \pi^0 e^+\nu_e of 1.5.Comment: 10 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits

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    Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)
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