Quark + diquark description of nucleon elastic electromagnetic form factors

Working with a Poincaré-covariant quark + diquark, q(qq), Faddeev equation approach to nucleon structure, a refined symmetry preserving current for electron + nucleon elastic scattering is developed. The parameters in the interaction current are chosen to ensure that the q(qq) picture reproduces selected results from contemporary 3-body analyses of nucleon elastic electromagnetic form factors. Although the subset of fitted results is small, the q(qq) picture reproduces almost all the 3-body predictions and often results in better agreement with available data. Notably, the q(qq) framework predicts a zero in , the absence of such a zero in , and a zero in the proton’s d-quark Dirac form factor. Derived q(qq) results for proton flavour-separated light-front-transverse number and anomalous magnetisation densities are also discussed. With the q(qq) framework thus newly benchmarked, one may proceed to comparisons with a broader array of 3-body results. This may enable new steps to be made toward answering an important question, viz. is the quark + fully-interacting diquark picture of baryon structure only a useful phenomenology or does it come close to expressing robust features of baryon structure?