D-state configurations in the electromagnetic form factors of the nucleon and the [formula omitted] resonance

Abstract

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 R EM ratio for the Δ ( 1232 ) → N γ transition closer to the empirical values in instant and point form kinematics. The calculated R SM 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 R EM and R SM , 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.