Sidewise dispersion relations and the structure of the nucleon vertex

Abstract

We revisit sidewise dispersion relations as a method to relate the nucleon off-shell form factor to observable quantities, namely the meson-nucleon scattering phase shifts. It is shown how for meson-nucleon scattering a redefinition of the intermediate fields leaves the scattering amplitude invariant, but changes the behavior of the off-shell form factor as expressed through dispersion relations, thus showing representation dependence. We also employ a coupled-channel unitary model to test the validity of approximations concerning the influence of inelastic channels in the sidewise dispersion relation method.

29 pages. Uuencoded gz-compressed tar file; includes RevTeX source plus 3 postscript figures incorporated with epsfig.sty plus 3 LaTeX figures using eepic.sty (included). Complete postscript file available via WWW at http://www.nikhefk.nikhef.nl/projects/Theory/preprints/preprints.html

References in corpus (5)

• The $\eta$NN Coupling in Eta Photoproduction
• pi N --> eta N and eta N --> eta N partial wave T-matrices in a coupled, three channel model
• Compton Scattering by a Pion and off--Shell Effects
• The off-shell electromagnetic form factors of pions and kaons in chiral perturbation theory
• The off-Shell Electromagnetic Vertex of the Nucleon in Chiral Perturbation Theory

Cited by in corpus (11)

• Form factors and photoproduction amplitudes
• Field transformations and simple models illustrating the impossibility of measuring off-shell effects
• Nucleon-nucleon bremsstrahlung: An example of the impossibility of measuring off-shell amplitudes
• Compton scattering in a unitary approach with causality constraints
• Hadron structure and the limitations of phenomenological models in electromagnetic reactions
• Dressing the nucleon in a dispersion approach
• On electromagnetic off-shell effects in proton-proton bremsstrahlung
• Lepton-Pair Production in Virtual Compton Scattering off the Proton
• Consistent off-shell $\pi NN$ vertex and nucleon self-energy
• The equivalence theorem and the Bethe-Salpeter equation
• In-medium meson properties and field transformations