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2 Chapter 1. IntroductionNucleon spectroscopyMapping out the baryonic spectrum remains a paramount issue in hadron physics. The masses,widths, and transition form factors of the nucleon’s excited states are invaluable tests of models aimedat understanding the internal structure of baryons. The experimental knowledge on excited nucleonstates is gathered bi-yearly by the Particle Data Group in the Review of Particle Physics (RPP) [1].Their major source of information stems from partial-wave analyses (PWA) of πN scattering data. Inparticular, the PWA performed by the Karlsruhe – Helsinki [2], Carnegie-Mellon – Berkeley [3] andGeorge-Washington – Virginia-Polytechnic-Institute (SAID) [4] groups. Resonances are identified byexamining the fitted amplitudes for poles in the complex energy plane. Alternatively, the amplitudesserve as input to coupled-channels (CC) PWA [5–10]. Besides the fitted elastic πN amplitudes,these analyses include data on inelastic channels and, in some cases, photon-induced processes toconstrain their results. Despite partial-wave solutions of comparable goodness of fit, one often obtainsconflicting information on the resonant content. Beyond the first few established nucleon excitations,many states are debated and the overall view on the resonance spectrum remains unclear [11].A similar observation can be made when the experimental picture is confronted with nucleon spectrapredicted by CQMs. The description of low-lying states is adequate. Yet, beyond the 1800-MeVmass range, an excessively dense spectrum is predicted. It is said that a number of resonances are“missing”. This might be an indication of the fact that the effective degrees of freedom should bere-examined, since alternative nucleon-structure models, such as quark-diquark models [12], envisionfar fewer resonant states. On the other hand, the missing-resonance conundrum could be a directconsequence of the unbalanced contribution of πN data to PWA.Strangeness productionElectromagnetic (EM) kaon production plays a key role in the ongoing theoretical and experimentalefforts to explore the dynamics of QCD in the confinement regime. Since the production mechanisminevitably involves quark-antiquark components of the nucleon’s sea, the reaction has the potentialto probe unexplored aspects of the nucleon’s structure. Hence, the presence of open strangenessin the final state holds out the prospect of finding some elusive resonant states. Several quarkmodelresults indicate that a number of unobserved resonances couple weakly to the πN final state,but have considerable branching fractions to alternative reaction channels, including those withstrangeness [13–15].The earliest work on EM strangeness production can be dated back to the sixties of the previouscentury [16–18]. These studies were held back by the limited accuracy of the data available atthat time. It was not until the advent of high-duty-cycle, high-intensity electron acceleratorsthat the theoretical interest in kaon production was rekindled. Adelseck et al. constructed a kaonphotoproductionoperator using a diagrammatic technique based on purely hadronic degrees offreedom [19]. This approach is known as the isobar model and has been applied to the analysisof kaon production in numerous studies [19–30]. In a different approach, quark models have beenused directly to describe the reaction dynamics [31–37]. Focusing on a correct high-energy limitfor the kaon-production operator, a number of studies inspired by Regge phenomenology havebeen published [38–42]. In recent years, several groups have undertaken the task of incorporatingstrangeness production in CC formalisms [5, 10, 43–48]. Motivated by the prospect of a complete