Comparison of the high energy models for neutral meson photoproduction and the related hadronic processes

Abstract

To critically compare the Michigan and Argonne models we perform simultaneus fits to the high-energy data for [pi]0 and [nu] photoproduction together with that for the related hadronic vector meson production reactions, in particular that for [pi]+n --> [omega]p. Thus all constraints on these models are considered simultaneously. Particular attention is given to the strength of absoptive cuts in both models, and to the role of the B-meson exchange in filling dips in the Argonne model. We find that the [varrho]-Pomeron cuts (i.e. cuts associated with large helicity flip at the N vertex) are essential to introducing unnatural parity exchange in the Michigan model, and that the B-meson contribution is incapable of filling unwanted dips which appear in any model with nonsense wrong signature zeros as required by exchange degeneracy. The flip and non-flip [varrho] and [omega] coupling strengths at the N vertex are determined. Predictions are made for various polarization asymmetries for [gamma]p --> [pi]0p and [gamma]p --> [eta]p. The differential cross section for KL0p --> KS0p is calculated and compared with the existing data.