1999/06/15 by S. Kondratyuk, O. Scholten, Kondratyuk, S. +2
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.48550/arxiv.nucl-th/9906044
51 pages, 12 Postscript figures, using REVTeX. Submitted to Phys. Rev. C, added references
openalex publication_date 1999/06/15 · arxiv created 1999/06/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Form factors in the nucleon-photon vertex with one off-shell nucleon are calculated by dressing the vertex with pion loops up to infinite order. Cutting rules and dispersion relations are implemented in the model. Using the prescription of minimal substitution we construct a γπN N vertex and show that it has to be included in the model in order that the Ward-Takahashi identity for the γN N vertex be fulfilled. The vertex is to be applied in a coupled-channel K-matrix formalism for Compton scattering, pion photoproduction and pion scattering. The form factors show a pronounced cusp structure at the pion threshold. As an illustration of a consistent application of the model, we calculate the cross section of Compton scattering. To provide gauge invariance in Compton scattering, a four-point γγN N contact term is constructed using minimal substitution.