3,626 research outputs found

    The Semileptonic Decay Fraction of B Mesons in the Light of Interfering Amplitudes

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    Consequences of the interference between spectator amplitudes for the lifetimes and semileptonic decay fractions of B^0 and B^+ mesons are discussed. Assuming duality and constructive interference between spectator amplitudes we are able to explain the low experimental value for the semileptonic decay fraction of BB mesons. Extracting these amplitudes from a fit to 11 exclusive hadronic B decay fractions we find a_1 = 1.05 +/- 0.03 +/- 0.10, a_2 =+0.227 +/ 0.012 +/- 0.022, an inclusive semileptonic decay fraction of (11.2 +/- 0.5 +/- 1.7), and a lifetime ratio tau(B^+) / tau(B^0) = 0.83 +/- 0.01 +/- 0.01.Comment: 9 page

    A Review of Hadronic and Rare B Decays

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    We review recent experimental results on B meson decays. These include measurements of the inclusive production of charmed and non-charmed mesons and baryons, the reconstruction of a large number of exclusive hadronic final states with charmed mesons, the search for exclusive hadronic final states without charmed mesons, and the first observation of the decay B-> K* gamma which is described by an electromagnetic penguin diagram. The theoretical implications of these results will be considered. The figures can be obtained in postscript format EMAIL from [email protected]: 77 pages; CLNS 93/1261, UH-511-778-93, OHSTPY-HEP-E-93-018, HEPSY 93-1

    Cosmological constraints from the convergence 1-point probability distribution

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    We examine the cosmological information available from the 1-point probability distribution (PDF) of the weak-lensing convergence field, utilizing fast L-PICOLA simulations and a Fisher analysis. We find competitive constraints in the Ωm\Omega_m-σ8\sigma_8 plane from the convergence PDF with 188 arcmin2188\ arcmin^2 pixels compared to the cosmic shear power spectrum with an equivalent number of modes (ℓ<886\ell < 886). The convergence PDF also partially breaks the degeneracy cosmic shear exhibits in that parameter space. A joint analysis of the convergence PDF and shear 2-point function also reduces the impact of shape measurement systematics, to which the PDF is less susceptible, and improves the total figure of merit by a factor of 2−32-3, depending on the level of systematics. Finally, we present a correction factor necessary for calculating the unbiased Fisher information from finite differences using a limited number of cosmological simulations.Comment: 10 pages, 5 figure
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