22,714 research outputs found
Strong Isospin Breaking in CP-even and CP-odd K -> pi pi Decays
Complete next-to-leading (chiral) order (NLO) expressions for the strong
isospin-breaking (IB) contributions in K -> pi pi are used to discuss (1) for
CP-even, the impact on the magnitude of the Delta I=1/2 Rule, and (2) for
CP-odd, the strong IB correction, Omega_st, for the gluonic penguin
contribution to epsilon'/epsilon, with particular emphasis on the strong
low-energy constant (LEC) and loop contributions, numerical values for which
are model-independent at NLO.Comment: 4 pages. Contribution to the proceedings of the 7th Conference on the
Intersections of Particle and Nuclear Physics (CIPANP), May 22-28 2000,
Quebec City, Canada. Uses AIP 6x9 LaTeX styl
Isospin Breaking in the Extraction of Isovector and Isoscalar Spectral Functions from e^+e^- --> hadrons
A finite energy sum rule (FESR) analysis of the isospin-breaking vector
current correlator is used to determine the
isospin-breaking electromagnetic (EM) decay constants of the low-lying vector
mesons. These results are used to evaluate the corrections required to extract
the flavor diagonal 33 and 88 resonance contributions from the full resonance
EM contributions to the EM spectral function. A large (~15%) correction is
found in the case of the omega contribution to the isoscalar spectral function.
The implications of these results for sum rules based on the
isovector-isoscalar spectral difference are considered.Comment: Presentation to the 3rd International Conference on Symmetries in
Subatomic Physics, Adelaide, Mar. 13-17, 200
Modeling Network Populations via Graph Distances
This article introduces a new class of models for multiple networks. The core
idea is to parametrize a distribution on labelled graphs in terms of a
Fr\'{e}chet mean graph (which depends on a user-specified choice of metric or
graph distance) and a parameter that controls the concentration of this
distribution about its mean. Entropy is the natural parameter for such control,
varying from a point mass concentrated on the Fr\'{e}chet mean itself to a
uniform distribution over all graphs on a given vertex set. We provide a
hierarchical Bayesian approach for exploiting this construction, along with
straightforward strategies for sampling from the resultant posterior
distribution. We conclude by demonstrating the efficacy of our approach via
simulation studies and two multiple-network data analysis examples: one drawn
from systems biology and the other from neuroscience.Comment: 33 pages, 8 figure
Experimental Studies of NaCs
We present experimental studies of excited electronic states of the NaCs molecule that are currently underway in our laboratory. The optical-optical double resonance method is used to obtain Doppler-free excitation spectra for several excited states. These data are being used to obtain RydbergKlein-Rees (RKR) or Inverse Perturbation Approach (IPA) potential curves for these states. We are also trying to map the bound portion of the 1(a) 3Σ + potential using resolved laser-induced fluorescence and Fourier transform spectroscopy to record transitions into the shallow well. Bound-free spectra from single ro-vibrational levels of electronically excited states to the repulsive wall of the 1(a) 3Σ + state are also being recorded. Using the previously determined excited state potentials, we can fit the repulsive wall of the 1(a) 3Σ + state to reproduce the experimental spectra using LeRoy’s BCONT program. A slightly modified version of BCONT will also be used to fit the relative transition dipole moments, µe(R), as a function of internuclear separation R, for the various bound-free electronic transitions
Experimental Studies of the NaCs 53Î 0 and a3ÎŁ+ States
We report high resolution measurements of 372 NaCs 53Π0(v, J) ro-vibrational level energies in the range 0 ≤ v ≤ 22. The data have been used to construct NaCs 53Π0 potential energy curves using the Rydberg–Klein-Rees and inverted perturbation approximation methods. Bound-free 53Π0(v, J) → 1(a)3Σ+ emission has also been measured, and is used to determine the repulsive wall of the 1(a)3Σ+ state and the 53Π0 → 1(a)3Σ+ relative transition dipole moment function. Hyperfine structure in the 53Π0 state has not been observed in this experiment. This null result is explained using a simple vector coupling model
Consumer Willingness to Pay for Irradiated Poultry Products
A probit model for whether or not consumers would buy irradiated poultry products is estimated jointly with an OLS equation for the price premiums that consumers are willing to pay for irradiated chicken breast meat. The results suggest that educating consumers about irradiation would be beneficial to the food industry.Consumer/Household Economics,
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