4,071 research outputs found
Correlations of Partial Waves for Multi-Reaction Analyses
In the search for missing baryonic resonances, many analyses include data
from a variety of pion- and photon-induced reactions. For elastic
scattering, however, usually the partial waves of the SAID or other groups are
fitted, instead of data. We provide the partial-wave covariance matrices needed
to perform correlated fits, in which the obtained equals the
actual up non-linear and normalization corrections. For any analysis
relying on partial waves extracted from elastic pion scattering, this is a
prerequisite to assess the significance of resonance signals and to assign any
uncertainty on results. The influence of systematic errors is also considered.Comment: 7 pages, 3 figures; Acknowledgements update
Sensitivity to the pion-nucleon coupling constant in partial-wave analyses of elastic pi-N and NN scattering and pion photoproduction
We summarize results obtained in our studies of the pion-nucleon coupling
constant. Several different techniques have been applied to pi-N and NN elastic
scattering data, and the existing database for single-pion photoproduction. The
most reliable determination comes from pi-N elastic scattering. The sensitivity
in this reaction was found to be greater, by at least a factor of 3, when
compared with analyses of NN elastic scattering or single-pion photoproduction.Comment: 10 pages, 1 figure. Talk given at the Uppsala workshop on the
pion-nucleon coupling constan
New Jersey\u27s school funding policy from 2002 to the present and its impact on student achievement
The purpose of the study was to identify how school districts were impacted by the state aid decisions made from 2002 and to then determine if there was a relationship between the excess or shortfall of state aid received and the achievement of students in each district during the same period as measured by standards used to identify schools in need of improvement. The study included 540 non-Abbott school districts and considered enrollment growth, change in total budget, and change in state aid. It used the 2004-2005 report of schools in need of improvement to identify districts that were failing to achieve. As more years passed from the 2001-2002 base year, the last year in which actual district enrollments were used to calculate the state aid to be received by each district, there was a greater disparity in the amount of state aid received by the school districts in terms of changes in district enrollments. At the same time, more districts were being identified as having schools in need of improvement. No direct causal relationship was identified, however parallels were identified that warrant further study
A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses
A new generation of complete experiments in pseudoscalar meson
photo-production is being pursued at several laboratories. While new data are
emerging, there is some confusion regarding definitions of asymmetries and the
conventions used in partial wave analyses (PWA). We present expressions for
constructing asymmetries as coordinate-system independent ratios of cross
sections, along with the names used for these ratios by different PWA groups.
(This update reflects a recent change in the definition of an asymmetry as used
by one group.)Comment: v2: This update reflects a recent change in the definition of an
asymmetry as used by one PWA group -see Table 1. v1: 4 pages. Contribution to
the proceedings of the 8th International Workshop on the Physics of Excited
Nucleons (NSTAR2011), Newport News, VA, USA, May 17-20, 201
Fast Shocks From Magnetic Reconnection Outflows
Magnetic reconnection is commonly perceived to drive flow and particle
acceleration in flares of solar, stellar, and astrophysical disk coronae but
the relative roles of different acceleration mecha- nisms in a given
reconnection environment are not well understood. We show via direct numerical
simulations that reconnection outflows produce weak fast shocks, when
conditions for fast recon- nection are met and the outflows encounter an
obstacle. The associated compression ratios lead to a Fermi acceleration
particle spectrum that is significantly steeper than the strong fast shocks
commonly studied, but consistent with the demands of solar flares. While this
is not the only acceleration mechanism operating in a reconnection environment,
it is plausibly a ubiquitous one
Effect of thermodynamics on ion mixing
Ion mixing of elemental 4d-5d metallic bilayers at 77 K by 600 keV Xe + + ions has been studied to test the validity of the phenomenological model of ion mixing that predicts a dependence on the chemical heats of mixing, DeltaHmix, and on the cohesive energies, DeltaHcoh, of the bilayer elements. A series of samples was chosen to minimize the variation in kinematical properties between samples while maximizing the variation in heats of mixing. The experimental results agree well with the model's predictions, and the experimentally determined constants K1=0.034 Ã… and K2=27 agree with those of previous work
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