15,165 research outputs found
An ultra-weak sector, the strong CP problem and the pseudo-Goldstone dilaton
In the context of a Coleman-Weinberg mechanism for the Higgs boson mass, we
address the strong CP problem. We show that a DFSZ-like invisible axion model
with a gauge-singlet complex scalar field S, whose couplings to the Standard
Model are naturally ultra-weak, can solve the strong CP problem and
simultaneously generate acceptable electroweak symmetry breaking. The
ultra-weak couplings of the singlet S are associated with underlying
approximate shift symmetries that act as custodial symmetries and maintain
technical naturalness. The model also contains a very light pseudo-Goldstone
dilaton that is consistent with cosmological Polonyi bounds, and the axion can
be the dark matter of the universe. We further outline how a SUSY version of
this model, which may be required in the context of Grand Unification, can
avoid introducing a hierarchy problem.Comment: 9 page
Ultra-weak sector, Higgs boson mass, and the dilaton
The Higgs boson mass may arise from a portal coupling to a singlet field
which has a very large VEV . This requires a
sector of "ultra-weak" couplings , where . Ultra-weak couplings are technically naturally small
due to a custodial shift symmetry of in the
limit. The singlet field has properties similar to a pseudo-dilaton.
We engineer explicit breaking of scale invariance in the ultra-weak sector via
a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak
couplings.Comment: 6 page
A hydrological analysis of East Australian floods using Nimbus 5 electrically scanning microwave radiometer data
A chronology of a major Australian flood in 1974 is presented using Nimbus 5 Passive Microwave Data (ESMR) and other conventional and satellite supporting data
Method and apparatus for using magneto-acoustic remanence to determine embrittlement
A method and apparatus for testing steel components for temperature embrittlement uses magneto-acoustic emission to nondestructively evaluate the component are presented. Acoustic emission signals occur more frequently at higher levels in embrittled components. A pair of electromagnets are used to create magnetic induction in the test component. Magneto-acoustic emission signals may be generated by applying an AC current to the electromagnets. The acoustic emission signals are analyzed to provide a comparison between a component known to be unembrittled and a test component. Magnetic remanence is determined by applying a DC current to the electromagnets and then by turning the magnets off and observing the residual magnetic induction
Dual-doped thermographic phosphor particles as surrogates for green fluorescent protein-labeled cells in tests of cytometric neurocatheters
We investigated the laser-induced fluorescence of particles of a compound thermographic phosphorLa2O2S:Eu(1%) and Gd2O2S:Eu(1%) to see if they can serve as a surrogate for cells transfected with the green fluorescent protein, in tests of neurocatheters used for intraparenchymal celldelivery. At an excitation wavelength of 337 nm and a concentration of ≈2×106 particles ml−1, the resulting slurries produced fluorescence intensities at 625 nm that were within a factor of 2 of those produced by similar number densities of relevant cells, thus suggesting the utility of this approach
Changing the Order of Mathematics Test Items: Helping or Hindering Student Performance?
This paper recounts an experiment by a mathematics professor who primarily teaches mathematics majors. The main question explored is whether the ordering of the questions makes a difference as to how students perform in a test. More specifically we focus here on the following research questions:\ (1) Does arranging a math test with easy-to-hard items versus hard-to-easy items impact student performance? and (2) If so, does item order impact male and female mathematics majors and non-majors in unique ways? We examine data collected over multiple semesters with several different classes. We find that for most of the mathematics students who were examined, the ordering of the questions on a test did not impact performance. However, female majors performed better on classroom exams when the test was arranged with the more difficult questions presented first. Readers who are interested in teaching mathematics, educational psychology, or gender issues in the classroom may find our results intriguing
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