67,601 research outputs found
Vector meson photoproduction in the quark model
We present a quark model study of the meson photoproduction near
threshold. With a limited number of parameters, all the data in history are
reproduced. The roles played by the {\it s}- and {\it u}-channel processes
(resonance excitations and nucleon pole terms), as well as the {\it t}-channel
{\it natural} (Pomeron) and {\it unnatural} parity (pion) exchanges are
clarified. This approach provides a framework for systematic study of vector
meson photoproduction near threshold.Comment: 4 pages, 3 figures; Talk given at NSTAR2001, Mainz, Germany, Mar.
7-10, 200
Variational-Iterative Solution of Ground State for Central Potential
The newly developed iterative method based on Green function defined by
quadratures along a single trajectory is combined with the variational method
to solve the ground state quantum wave function for central potentials. As an
example, the method is applied to discuss the ground state solution of Yukawa
potential, using Hulthen solution as the trial function.Comment: 9 pages with 1 tabl
Using Qualitative Hypotheses to Identify Inaccurate Data
Identifying inaccurate data has long been regarded as a significant and
difficult problem in AI. In this paper, we present a new method for identifying
inaccurate data on the basis of qualitative correlations among related data.
First, we introduce the definitions of related data and qualitative
correlations among related data. Then we put forward a new concept called
support coefficient function (SCF). SCF can be used to extract, represent, and
calculate qualitative correlations among related data within a dataset. We
propose an approach to determining dynamic shift intervals of inaccurate data,
and an approach to calculating possibility of identifying inaccurate data,
respectively. Both of the approaches are based on SCF. Finally we present an
algorithm for identifying inaccurate data by using qualitative correlations
among related data as confirmatory or disconfirmatory evidence. We have
developed a practical system for interpreting infrared spectra by applying the
method, and have fully tested the system against several hundred real spectra.
The experimental results show that the method is significantly better than the
conventional methods used in many similar systems.Comment: See http://www.jair.org/ for any accompanying file
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