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 $B$ 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 $B$ 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.