  The first challenge faced in investigating the strong interaction from
partially explored, where meson-cloud degrees of freedom dominate, to still
unexplored distance scales, where the dressed-quark contributions are the
dominating degrees of freedom, is to find an experiment that allows to measure
observables that are probing this evolving nonperturbative QCD regime over the
full range. Baryon spectroscopy can establish more sensitively, and in an
almost model-independent way, nucleon excitation and non-resonant reaction
amplitudes by complete measurements of pseudo-scalar meson photoproduction off
nucleons. Elastic and transition form factors can then trace this evolution by
measurements of elastic electron scattering and exclusive single-meson and
double-pion electroproduction cross sections off the nucleon that will be
extended to higher momentum transfers with the energy-upgraded CEBAF beam at
JLab to study the dressed quark degrees of freedom, where their strong
interaction is responsible for the ground and excited nucleon state formations.
After establishing unprecedented high-precision data, the immanent next
challenge is a high-quality analysis to extract these relevant electrocoupling
parameters for various resonances that then can be compared to state of the art
models and QCD-based calculations. Recent results demonstrate the status of the
analysis and pinpoint further challenges, including those to establish
QCD-based results directly from the experimental data.
