1,485 research outputs found
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
The psychology of indicative conditionals and conditional bets
There is a new Bayesian, or probabilistic, paradigm in the psychology of reasoning, with new psychological accounts of the indicative conditional of natural language. In psychological experiments in this new paradigm, people judge that the probability of the indicative conditional, P(if A then C), is the conditional probability of C given A, P(C | A). In other experiments, participants respond with what has been called the 'de- fective' truth table: they judge that if A then C is true when A holds and C holds, is false when A holds and C does not, and is neither true nor false when A does not hold. We argue that these responses are not 'defective' in any negative sense, as many psychologists have implied. We point out that a number of normative researchers, including de Finetti, have proposed such a table for various coherent interpretations of the third value. We review the relevant general tables in the normative literature, in which there is a third value for A and C and the logically compound forms of the natural language conditional, negation, conjunction, disjunction, and the material conditional. We describe the results of an experiment on which of these tables best describes ordinary people's judgements when the third value is interpreted as indicating uncertainty
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
QCD Factorization for Decays: Strong Phases and CP Violation in the Heavy Quark Limit
We show that, in the heavy quark limit, the hadronic matrix elements that
enter meson decays into two light mesons can be computed from first
principles, including `non-factorizable' strong interaction corrections, and
expressed in terms of form factors and meson light-cone distribution
amplitudes. The conventional factorization result follows in the limit when
both power corrections in and radiative corrections in are
neglected. We compute the order- corrections to the decays
, and in the heavy
quark limit and briefly discuss the phenomenological implications for the
branching ratios, strong phases and CP violation.Comment: 6 pages, 1 figur
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
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
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
Reinstatement of "germinal epithelium" of the ovary
BACKGROUND: The existing dogma that the former term ovarian "germinal epithelium" resulted from a mistaken belief that it could give rise to new germ cells is now strongly challenged. DISCUSSION: Two years ago, a research group of the University of Tennessee led by Antonin Bukovsky successfully demonstrated the oogenic process from the human ovarian covering epithelium now commonly called the ovarian surface epithelium. They showed the new oocyte with zona pellucida and granulosa cells, both originated from the surface epithelium arising from mesenchymal cells in the tunica albuginea, and stressed that the human ovary could form primary follicles throughout the reproductive period. This gives a big impact not only to the field of reproductive medicine, but also to the oncologic area. The surface epithelium is regarded as the major source of ovarian cancers, and most of the neoplasms exhibit the histology resembling müllerian epithelia. Since the differentiating capability of the surface epithelium has now expanded, the histologic range of the neoplasms in this category may extend to include both germ cell tumors and sex cord-stromal cell tumors. SUMMARY: Since the oogenic capability of ovarian surface cells has been proven, it is now believed that the oocytes can originate from them. The term "germinal epithelium", hence, might reasonably be reinstated
Double-blind reviewing and gender biases at EvoLang conferences
A previous study of reviewing at the Evolution of Language conferences found effects that suggested that gender bias against female authors was alleviated under double-blind review at EvoLang 11. We update this analysis in two specific ways. First, we add data from the most recent EvoLang 12 conference, providing a comprehensive picture of the conference over five iterations. Like EvoLang 11, EvoLang 12 used double-blind review, but EvoLang 12 showed no significant difference in review scores between genders. We discuss potential explanations for why there was a strong effect in EvoLang 11, which is largely absent in EvoLang 12. These include testing whether readability differs between genders, though we find no evidence to support this. Although gender differences seem to have declined for EvoLang 12, we suggest that double-blind review provides a more equitable evaluation process
Unitarity of Quantum Theory and Closed Time-Like Curves
Interacting quantum fields on spacetimes containing regions of closed
timelike curves (CTCs) are subject to a non-unitary evolution . Recently, a
prescription has been proposed, which restores unitarity of the evolution by
modifying the inner product on the final Hilbert space. We give a rigorous
description of this proposal and note an operational problem which arises when
one considers the composition of two or more non-unitary evolutions. We propose
an alternative method by which unitarity of the evolution may be regained, by
extending to a unitary evolution on a larger (possibly indefinite) inner
product space. The proposal removes the ambiguity noted by Jacobson in
assigning expectation values to observables localised in regions spacelike
separated from the CTC region. We comment on the physical significance of the
possible indefiniteness of the inner product introduced in our proposal.Comment: 13 pages, LaTeX. Final revised paper to be published in Phys Rev D.
Some changes are made to expand our discussion of Anderson's Proposal for
restoring unitarit
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