6,523 research outputs found
Electric Polarizability of Neutral Hadrons from Lattice QCD
By simulating a uniform electric field on a lattice and measuring the change
in the rest mass, we calculate the electric polarizability of neutral mesons
and baryons using the methods of quenched lattice QCD. Specifically, we measure
the electric polarizability coefficient from the quadratic response to the
electric field for 10 particles: the vector mesons and ; the
octet baryons n, , , , and ;
and the decouplet baryons , , and .
Independent calculations using two fermion actions were done for consistency
and comparison purposes. One calculation uses Wilson fermions with a lattice
spacing of fm. The other uses tadpole improved L\"usher-Weiss gauge
fields and clover quark action with a lattice spacing fm. Our results
for neutron electric polarizability are compared to experiment.Comment: 25 pages, 20 figure
Solution growth of Triglycine Sulfate (TGS) crystals on the International Microgravity Laboratory (IML-1)
An experiment was planned for the International Microgravity Laboratory (IML-1) to be launched around Feb. 1991. Crystals of triglycine sulfate (TGS) will be grown by low temperature solution crystal growth technique using a multiuser facility called Fluid Experiment System (FES). A special cooled sting technique of solution crystal growth will be used where heat is extracted from the seed crystal through a semi-insulating sting, thereby creating the desired supersaturation near the growing crystal. Also, a holocamera will be used to provide tomography of the three dimensional flow field and particle image displacement velocimetry to monitor the convective flows
Fidelity for displaced squeezed states and the oscillator semigroup
The fidelity for two displaced squeezed thermal states is computed using the
fact that the corresponding density operators belong to the oscillator
semigroup.Comment: 3 pages, REVTEX, no figures, submitted to Journal of Physics A, May
5, 199
Decuplet Baryon Structure from Lattice QCD
The electromagnetic properties of the SU(3)-flavor baryon decuplet are
examined within a lattice simulation of quenched QCD. Electric charge radii,
magnetic moments, and magnetic radii are extracted from the E0 and M1 form
factors. Preliminary results for the E2 and M3 moments are presented giving the
first model independent insight to the shape of the quark distribution in the
baryon ground state. As in our octet baryon analysis, the lattice results give
evidence of spin-dependent forces and mass effects in the electromagnetic
properties. The quark charge distribution radii indicate these effects act in
opposing directions. Some baryon dependence of the effective quark magnetic
moments is seen. However, this dependence in decuplet baryons is more subtle
than that for octet baryons. Of particular interest are the lattice predictions
for the magnetic moments of and for which new recent
experimental measurements are available. The lattice prediction of the
ratio appears larger than the experimental ratio, while the
lattice prediction for the magnetic moment ratio is in good
agreement with the experimental ratio.Comment: RevTeX manuscript, 34 pages plus 21 figures (available upon request
Psychosocial factors predicting first-year college student success
This study made use of a model of college success that involves students achieving academic goals and life satisfaction. Hierarchical regressions examined the role of six psychosocial factors for college success among 579 first-year college students. Academic self-efficacy and organization and attention to study were predictive of first semester grade point average (GPA) when controlling relevant demographic factors. Academic self-efficacy was even predictive of end-of-year GPA when controlling previous, first-semester GPA. Mediation analyses revealed that first-semester GPA was an important mediator between these two psychosocial variables and end-of-year GPA. Additional psychosocial variables were predictive of college students’ life satisfaction: stress and time management, involvement with college activity, and emotional satisfaction with academics. We explore how formulating interventions on the basis of psychosocial factors offers an avenue for students to address specific attitudes, emotions, and behaviors that relate to college success
Prototype 9.7 m Schwarzschild-Couder telescope for the Cherenkov Telescope Array: status of the optical system
The Cherenkov Telescope Array (CTA) is an international project for a
next-generation ground-based gamma ray observatory, aiming to improve on the
sensitivity of current-generation experiments by an order of magnitude and
provide energy coverage from 30 GeV to more than 300 TeV. The 9.7m
Schwarzschild-Couder (SC) candidate medium-size telescope for CTA exploits a
novel aplanatic two-mirror optical design that provides a large field of view
of 8 degrees and substantially improves the off-axis performance giving better
angular resolution across all of the field of view with respect to
single-mirror telescopes. The realization of the SC optical design implies the
challenging production of large aspherical mirrors accompanied by a
submillimeter-precision custom alignment system. In this contribution we report
on the status of the implementation of the optical system on a prototype 9.7 m
SC telescope located at the Fred Lawrence Whipple Observatory in southern
Arizona.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Busan, Korea. All CTA contributions at arXiv:1709.0348
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