17 research outputs found
Measurement of the B-Meson Inclusive Semileptonic Branching Fraction and Electron-Energy Moments
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
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
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
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 and
Using 4.8 fb of data taken with the CLEO II detector, the branching
fraction for the Cabibbo-suppressed decay measured
relative to the Cabibbo favored decay is found to be
. Using and from unitarity
constraints, we determine We
also present a 90% confidence level upper limit for the branching ratio of the
decay relative to that for 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
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)
