Pion Production Model - Connection between Dynamics and Quark Models

We discuss the difficulties in testing the hadron models by using the N^* parameters extracted from the empirical amplitude analyses of the pi-N and gamma-N reaction data. As an alternative or perhaps a more advantageous approach, we present a Hamiltonian formulation that can relate the pion production dynamics and the constituent quark models of N^* structure. The application of the approach in investigating the Delta and N^*(S_{11}) excitations is reviewed. It is found that while the Delta excitation can be described satisfactory, the pi-N scattering in S_{11} channel can not be described by the constituent quark models based on either the one-gluon-exchange or one-meson-exchange mechanisms. A phenomenological quark-quark potential has been constructed to reproduce the S_{11} amplitude.Comment: 11 pages, 4 figures, to be published in Proceedings of NSTAR2000 workshop held at Jefferson Laboratory, Feb., 200

Status of Dynamical Coupled-Channel Analysis by Collaboration@EBAC

The development and results of the Dynamical Coupled-Channels analysis by a collaboration at the Excited Baryon Analysis Center (EBAC) are reported.Comment: 5 pages, 4 figures. Contribution to Eleventh Conference on the Intersections of Particle and Nuclear Physics --- CIPANP 2012, May 28, 2012 - June 3, 2012, St. Petersburg, FL, US

The nature of stream-stream interaction in the large-scale structure of the solar wind

The stream-stream interaction between a slow solar wind and its leading faster solar wind is considered. A hydrodynamic model comprising double-layered rarefactions and recompressions is proposed toward understanding the observed large-scale structure near the trailing portion of a high-speed stream