Nuclear Physics A508 (1990) 197c-208c North-Holland 197c ~CLEON-APRON INTERACTION AT ~~~DIA~ ENERGIES AND REAM DUCT PRO~ESS~ CharlotteELSTER Dept. of Physics,The Ohio State University, 174 W. 18th Ave, Columbus, OH 43210, U.S.A. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPO A model for the nucleon-nucleon interaction at intermediate ener y based on a field theoretical Hamiltonian with nucleon-nucleon-meson and nucleon-de ta-meson evaluated in the frame work of time-ordered perturbation theor Ei vertices tex parameters determined by fitting NN data are applied to A k is described. The ver- scatterin reactions this model IS applied to proton-nucleus elastic scattering at interme rate energies. f. In nuclear 1. INTRODUCTION Motivated by a large amount of data on nucleon-nucleon scattering observables at in- termediate energies, nuclear pion production/ emission reactions and the controversy con- cerning the existence of conventional or exotic dibaryon resonances, extensive efforts have been made to understand the nucleon-nucleon interaction above pion production threshold. Several approaches have been made to construct models for the NN interaction including pion production, which may be roughly divided into two classes. First, there are the mod- els based on a form~ation of genuine unitary [NNn] three particle equations motivated originally by elastic nd scattering1*2. Those models explicitly include the rN scattering amplitudes P33 (delta resonance) and Prr (nucleon pole), usually employing a separable potential. The enormous work done by several groups differs in detail and philosophy, e.g. in some cases the major emphasis has been on the pp -+ nd reaction$, whereas in others the aim was to calculate spin observables for the three-body final state NN --+ NNrr4. The second class of models is based on the extension of conventional low energy potentials into the single pion production region 5*6~7*8~e. Most of these are based on coupled chan- nel calculations containing NN, NA and AA channels, and the single pion production is incorporated through the decay of the delta isobar doorway state. The main differences between these models has been the choice of kinematics, the description of the width of the delta resonance and the choice of the NN potential to be extrapolated. The present talk is organized into three parts: (i) I will describe common features and failures of NN models with emphasis on models based on meson theory. (ii) I will present a connection to TN scattering. (iii) Since the NN force may serve as a microscopic basis for nuclear many body reactions, I will demonstrate that the off-shell extrapolation of t-matrices obtained from a meson exchange model affects elastic proton nucleus scattering observables. 0375-9474 / 90 / $3.50 0 Elscvier Science Publishers B.V. (North-Holland)