D-state configurations in the electromagnetic form factors of the nucleon and the image resonance Original Research Article

The Δ–N electromagnetic transition form factors are calculated in a schematic Poincaré covariant quark model in three forms of relativistic kinematics. Addition of D-state components to pure S-state model wave functions, chosen so as to reproduce the empirical elastic electromagnetic nucleon form factors with single constituent currents, brings the calculated REM ratio for the Δ(1232)→Nγ transition closer to the empirical values in instant and point form kinematics. The calculated RSM ratio is insensitive to the D-state component. In front form kinematics the substantial violation of the angular condition for the spin 3/2 resonance transition amplitude in the impulse approximation prevents a unique determination of REM and RSM, both of which are very sensitive to D-state components. In no form of kinematics do D-state deformations of the rest frame baryon wave functions alone suffice for a description of the empirical values of these ratios.