1,416 research outputs found
An Experimental Overview of Gluonic Mesons
In this paper, I review the experimental situation for both glueballs and
hybrid mesons. Theoretical expectations are discussed, and a survey of what is
known about hybrid mesons and glueballs is undertaken. Good experimental
evidence exists for both states with exotic quantum numbers and a glueball
which is mixed with the nearby mesons, but a full understanding of these still
requires additional information.Comment: 17 pages, 6 figures, The Gluonics Excitations Workshop, Jefferson
Lab, Newport News, VA, May 14-16, 200
Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach
The complete expression for the intensity in pseudo-scalar meson
photoproduction with a polarized beam, target, and recoil baryon is derived
using a density matrix approach that offers great economy of notation. A
Cartesian basis with spins for all particles quantized along a single
direction, the longitudinal beam direction, is used for consistency and clarity
in interpretation. A single spin-quantization axis for all particles enables
the amplitudes to be written in a manifestly covariant fashion with simple
relations to those of the well-known CGLN formalism. Possible sign
discrepancies between theoretical amplitude-level expressions and
experimentally measurable intensity profiles are dealt with carefully. Our
motivation is to provide a coherent framework for coupled-channel partial-wave
analysis of several meson photoproduction reactions, incorporating recently
published and forthcoming polarization data from Jefferson Lab.Comment: 11 pages, 2 figure
Hay handling system comparison : baled hay vs. chopped hay
Digitized 2007 AES MoU.Includes bibliographical references (page 19)
Analysis, Visualization, and Transformation of Audio Signals Using Dictionary-based Methods
date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +0000date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +000
Type IIb Supernova SN 2011dh: Spectra and Photometry from the Ultraviolet to the Near-Infrared
We report spectroscopic and photometric observations of the Type IIb SN
2011dh obtained between 4 and 34 days after the estimated date of explosion
(May 31.5 UT). The data cover a wide wavelength range from 2,000 Angstroms in
the UV to 2.4 microns in the NIR. Optical spectra provide line profiles and
velocity measurements of HI, HeI, CaII and FeII that trace the composition and
kinematics of the SN. NIR spectra show that helium is present in the atmosphere
as early as 11 days after the explosion. A UV spectrum obtained with the STIS
reveals that the UV flux for SN 2011dh is low compared to other SN IIb. The HI
and HeI velocities in SN 2011dh are separated by about 4,000 km/s at all
phases. We estimate that the H-shell of SN 2011dh is about 8 times less massive
than the shell of SN 1993J and about 3 times more massive than the shell of SN
2008ax. Light curves (LC) for twelve passbands are presented. The maximum
bolometric luminosity of erg s occurred
about 22 days after the explosion. NIR emission provides more than 30% of the
total bolometric flux at the beginning of our observations and increases to
nearly 50% of the total by day 34. The UV produces 16% of the total flux on day
4, 5% on day 9 and 1% on day 34. We compare the bolometric light curves of SN
2011dh, SN 2008ax and SN 1993J. The LC are very different for the first twelve
days after the explosions but all three SN IIb display similar peak
luminosities, times of peak, decline rates and colors after maximum. This
suggests that the progenitors of these SN IIb may have had similar compositions
and masses but they exploded inside hydrogen shells that that have a wide range
of masses. The detailed observations presented here will help evaluate
theoretical models for this supernova and lead to a better understanding of SN
IIb.Comment: 23 pages, 14 figures, 9 tables, accepted by Ap
Schooling for violence and peace : how does peace education differ from ‘normal’ schooling?
This article reviews literature on the roles of schooling in both reproducing and actively perpetrating violence, and sets out an historical explanation of why schools are socially constructed in such a way as to make these roles possible. It then discusses notions of peace education in relation to one particular project in England before using empirical data from research on the project to examine contrasts between peace education approaches and ‘normal’ schooling from the viewpoints of project workers, pupils and teachers. It concludes that such contrasts and tensions do indeed exist and that this raises serious questions about the compatibility of peace education and formal schooling
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