1,631 research outputs found
Georgia\u27s Codification of Daubert: Narrowing the Admissibility of Novel Scientific Evidence in Georgia?
Polarization and `Model Independent' Extraction of from and
We briefly discuss the predictions of the heavy quark effective theory for
the semileptonic decays of a heavy pseudoscalar to a light one, or to a light
vector meson. We point out that measurement of combinations of differential
helicity decay rates at Cleo-c and the factories can provide a model
independent means of extracting the ratio
. We briefly discuss the corrections to this prediction.Comment: 8 pages, LaTeX, 1 figur
Hadronic Transitions among Quarkonium States in a Soft-Exchange-Approximation. Chiral Breaking and Spin Symmetry Breaking Processes
Although no asymptotic heavy quark spin symmetry, and even more no flavor
symmetry, are expected for systems such as quarkonium, a numerical discussion
shows that for some processes and in a preasymptotic region which may roughly
include charmonium and bottomonium, the use of the spin-symmetry may be useful
in conjunction with chiral symmetry for light hadrons (soft-exchange-
approximation regime, SEA). We continue our discussion of hadronic transitions
in the SEA-regime by studying in particular chiral breaking transitions such as
, , level splittings and transitions which break
both chiral and spin symmetry, such as , , and .Comment: LaTeX (style article) 19 pages, UGVA-DPT 12-80
UV asymptotically free QED as a broken YM theory in the unitary gauge
We compute the -function of a YM theory, broken to , by
evaluating the coupling constant renormalization in the broken phase. We
perform the calculation in the unitary gauge where only physical particles
appear and the theory looks like a version of QED containing massive charged
spin 1 particles. We consider an on-shell scattering process and after
verifying that the non-renormalizable divergences which appear in the Green's
functions cancel in the expression of the amplitude, we show that the coupling
constant renormalization is entirely due to the photon self-energy as in QED.
However we get the expected asymptotic freedom and the physical charge
decreases logarithmically as a function of the symmetry breaking scale.Comment: 8 page
Estimates with an Effective Chiral Lagrangian for Heavy Mesons
On the basis of an effective lagrangian incorporating approximate chiral
symmetry and heavy-quark spin and flavor symmetries, and by use of information
on leptonic decays, we estimate the effective coupling.Comment: UGVA-DPT 1992/07-779, BARI-TH/92-117 Revised version, September 1992,
LaTeX (style article), 7 page
Path Integrals, Density Matrices, and Information Flow with Closed Timelike Curves
Two formulations of quantum mechanics, inequivalent in the presence of closed
timelike curves, are studied in the context of a soluable system. It
illustrates how quantum field nonlinearities lead to a breakdown of unitarity,
causality, and superposition using a path integral. Deutsch's density matrix
approach is causal but typically destroys coherence. For each of these
formulations I demonstrate that there are yet further alternatives in
prescribing the handling of information flow (inequivalent to previous
analyses) that have implications for any system in which unitarity or coherence
are not preserved.Comment: 25 pages, phyzzx, CALT-68-188
Static observables of relativistic three-fermion systems with instantaneous interactions
We show that static properties like the charge radius and the magnetic moment
of relativistic three-fermion bound states with instantaneous interactions can
be formulated as expectation values with respect to intrinsically defined
wavefunctions. The resulting operators can be given a natural physical
interpretation in accordance with relativistic covariance. We also indicate how
the formalism may be generalized to arbitrary moments. The method is applied to
the computation of static baryon properties with numerical results for the
nucleon charge radii and the baryon octet magnetic moments. In addition we make
predictions for the magnetic moments of some selected nucleon resonances and
discuss the decomposition of the nucleon magnetic moments in contributions of
spin and angular momentum, as well as the evolution of these contributions with
decreasing quark mass.Comment: 13 pages, including 2 figures and 3 tables, submitted to Eur.Phys.J.
Isospin Multiplet Structure in Ultra--Heavy Fermion Bound States
The coupled Bethe--Salpeter bound state equations for a system,
where is a degenerate, fourth generation, super--heavy quark doublet,
are solved in several ladder approximation models. The exchanges of gluon,
Higgs and Goldstone modes in the standard model are calculated in the
ultra--heavy quark limit where weak and contributions are
negligible. A natural and multiplet pattern is found, with large
splittings occuring between the different weak iso--spin states when , the
quark masses, are larger than values in the range ,
depending on which model is used. Consideration of ultra--heavy quark lifetime
constraints and mass splitting constraints are reviewed to establish the
plausibility of lifetime and mass degeneracy requirements assumed for this
paper.Comment: 20 pages, 7 figures (hard copy available upon request), report#
KU-HEP-93-2
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