3,634 research outputs found
The Semileptonic Decay Fraction of B Mesons in the Light of Interfering Amplitudes
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 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
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
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 - plane from the convergence PDF with
pixels compared to the cosmic shear power spectrum with an
equivalent number of modes (). 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 , 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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