1. Doorway-resonance model for pion-nucleon D- and F-wave scattering
- Author
-
C. Assad, G.E. Parnell, and D.J. Ernst
- Subjects
Physics ,Nuclear and High Energy Physics ,Scattering ,Nuclear Theory ,Invariant (physics) ,Kinematic singularities ,Separable space ,Amplitude ,Classical mechanics ,Pion ,Quantum electrodynamics ,Nuclear Experiment ,Nucleon ,Communication channel - Abstract
A model for the resonant pion-nucleon D- and F-waves is developed which assumes that the pion-plus-nucleon couples to a resonance and that the resonance can serve as a doorway to the inelastic channels. With the use of simple form factors, the model is capable of reproducing the pion-nucleon phase shifts up to an energy of T π = 1.4 GeV if the coupling of the elastic channel to the inelastic channels is taken from data as input into the model. A value for the mass of the resonance that would result in the absence of the coupling to decay channels is extracted from the data utilizing the model. This is the mass that is most easily modeled by bag models. For the non-resonant D- and F-wave channels a separable potential model is used. This model, like the resonance model, is developed utilizing the invariant amplitude which is free of kinematic singularities and uses invariant norms and phase spaces. The model is also applied to the S-wave channels. A relation between the resonance model and the Chew-Low model is discovered and used to derive an extended Chew-Low model which is applied to the P 13 , P 31 , and P 33 channels. Implications of the model for understanding the range of the pion-nucleon interaction and the dynamic structure of the interaction are presented.
- Published
- 1990