15,402 research outputs found
Semi-Leptonic B Decay
The definitions and properties of elastic and inelastic Isgur-Wise form
factors are reviewed. The nature of the "missing" exclusive semi-leptonic decay
fraction is identified. The role that completeness sum rules play in relating
form factors, spectroscopy, and model building is outlined.Comment: Latex2.09, uses sprocl.sty and epsf.sty. 10 pages with 3 postscript
files included. Talk presented at the Conference on B Physics and CP
Violation, March 24-27, 1997, Honolulu, Hawai
CONFINEMENT IN RELATIVISTIC POTENTIAL MODELS
In relativistic potential models of quarkonia based on a Dirac-type of
equation with a local potential there is a sharp distinction between a linear
potential V which is vector-like and one which is scalar-like: There are
normalizable solutions for a scalar-like V but not for a vector-like V. It is
pointed out that if instead one uses an equation of the no-pair type, which is
more natural from the viewpoint of field theory, this somewhat bizarre
difference disappears.Comment: LaTeX, 4 page
Universal Behavior in Excited Heavy-Light and Light-Light Mesons
A common pattern of large orbital and radial excitations in heavy-light and
light-light mesons is demonstrated. Within a general potential model the Regge
slopes of the light degrees of freedom for these mesons are shown to be in the
ratio of two. The possibility of ``tower'' degeneracy occurs only with pure
scalar confinement.Comment: Latex, 10 pages, 2 figures placed using epsf.sty. Z-compressed
postscript version available at
http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-970.ps.Z or at
ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-970.ps.
Duality in Shearing Rheology Near the Athermal Jamming Transition
We consider the rheology of soft-core frictionless disks in two dimensions in
the neighborhood of the athermal jamming transition. From numerical simulations
of bidisperse, overdamped, particles, we argue that the divergence of the
viscosity below jamming is characteristic of the hard-core limit, independent
of the particular soft-core interaction. We develop a mapping from soft-core to
hard-core particles that recovers all the critical behavior found in earlier
scaling analyses. Using this mapping we derive a duality relation that gives
the exponent of the non-linear Herschel-Bulkley rheology above jamming in terms
of the exponent of the diverging viscosity below jamming.Comment: 5 pages, 4 figures. Manuscript revisions: new title, additional text
concerning connections to experiment, revised Fig. 4, other minor changes and
clarifications in text. Conclusions remain essentially unchanged. Accepted
for publication in Phys. Rev. Let
Semi-leptonic B decays into higher charmed resonances
We apply HQET to semi-leptonic meson decays into a variety of excited
charm states. Using three realistic meson models with fermionic light degrees
of freedom, we examine the extent that the sum of exclusive single charmed
states account for the inclusive semi-leptonic decay rate. The consistency
of form factors with the Bjorken and Voloshin sum rules is also investigated.Comment: Latex, 27 pages. A few references and errors corrected, to appear in
Phys. Rev.
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