1,902 research outputs found
Composite Skyrme Model with Vector Mesons
We study the composite Skyrme model, proposed by Cheung and G\"{u}rsey,
introducing vector mesons in a chiral Lagrangian. We calculate the static
properties of baryons and compare with results obtained from models without
vector mesons.Comment: LaTeX, 9 pages, 3 figures, to be published in Phys. Rev.
First test of correction of the orthopositronium decay rate
Positronium is an ideal system for the research of the bound state QED. New
precise measurement of orthopositronium decay rate has been performed with an
accuracy of 150 ppm. This result is consistent with the last three results and
also the 2nd order correction. The result combined with the last three is
7.0401 (100 ppm), which is consistent with the
2nd order correction and differs from the 1st order calculation by 2.6
It is the first test to validate the 2nd order correction.Comment: will be submitted to Phys. Lett.
How System Errors Affect Aircrew Resource Management (CRM)
System errors, both mechanical and human in nature, can have a grave effect on aircrew judgement in flight. The effects of these errors can be massively compounded during emergency situations. Crew Resource Management (CRM) is an important process aircrews can utilize to minimize risks and enhance assessments. The employment of this technique can be validated by aviation mishaps over the last three decades and how system errors increased the probability of the incident occurring. Suggestions can be made to further prevent similar accidents from occurring in the future utilizing historical aeronautical records. This paper outlines an approach by which systems errors can be recognized and prevented using CRM. It is the hope of the authors that employing such an approach will drastically decrease the incidence rate and severity of aviation mishaps due to systems errors. 2015 The Authors
Slow relaxation of conductance of amorphous hopping insulators
We discuss memory effects in the conductance of hopping insulators due to
slow rearrangements of structural defects leading to formation of polarons
close to the electron hopping states. An abrupt change in the gate voltage and
corresponding shift of the chemical potential change populations of the hopping
sites, which then slowly relax due to rearrangements of structural defects. As
a result, the density of hopping states becomes time dependent on a scale
relevant to rearrangement of the structural defects leading to the excess time
dependent conductivity.Comment: 6 pages, 1 figur
Baryons with Two Heavy Quarks as Solitons
Using the chiral soliton model and heavy quark symmetry we study baryons
containing two heavy quarks. If there exists a stable (under strong
interactions) meson consisting of two heavy quarks and two light ones, then we
find that there always exists a state of this meson bound to a chiral soliton
and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a
baryon containing two heavy anti-quarks and five light quarks, or a
``heptaquark".Comment: 7 pages and 2 postscript figures appended, LaTex, UCI-TR 94-3
Two Skyrmion Dynamics with Omega Mesons
We present our first results of numerical simulations of two skyrmion
dynamics using an -meson stabilized effective Lagrangian. We consider
skyrmion-skyrmion scattering with a fixed initial velocity of , for
various impact parameters and groomings. The physical picture that emerges is
surprisingly rich, while consistent with previous results and general
conservation laws. We find meson radiation, skyrmion scattering out of the
scattering plane, orbiting and capture to bound states.Comment: 19 pages, 22 figure
Modeling the transmission and thermal emission in a pupil image behind the Keck II adaptive optics system
The design and performance of astronomical instruments depend critically on the total system throughput as well as the background emission from the sky and instrumental sources. In designing a pupil stop for background- limited imaging, one seeks to balance throughput and background rejection to optimize measurement signal-to-noise ratios. Many sources affect transmission and emission in infrared imaging behind the Keck Observatoryâs adaptive optics systems, such as telescope segments, segment gaps, secondary support structure, and AO bench optics. Here we describe an experiment, using the pupil-viewing mode of NIRC2, to image the pupil plane as a function of wavelength. We are developing an empirical model of throughput and background emission as a function of position in the pupil plane. This model will be used in part to inform the optimal design of cold pupils in future instruments, such as the new imaging camera for OSIRIS
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