The reactions γp → π 0 p and γp → π + n are analyzed in a semi-phenomenological approach up to E ∼ 2.3 GeV. Fits to differential cross section and single and double polarization observables are performed. A good overall reproduction of the available photoproduction data is achieved. The Jülich2012 dynamical coupled-channel model -which describes elastic πN scattering and the world data base of the reactions πN → ηN , KΛ, and KΣ at the same time -is employed as the hadronic interaction in the final state. The framework guarantees analyticity and, thus, allows for a reliable extraction of resonance parameters in terms of poles and residues. In particular, the photocouplings at the pole can be extracted and are presented.

Elastic πN scattering and the world data of the family of reactions π − p → ηn, K 0 Λ, K 0 Σ 0 , K + Σ − , and π + p → K + Σ + are described simultaneously in an analytic, unitary, coupled-channel approach. SU(3) flavor symmetry is used to relate both the t-and the u-channel exchanges that drive the meson-baryon interaction in the different channels. Angular distributions, polarizations, and spin-rotation parameters are compared with available experimental data. Partial-wave amplitudes are determined and the resonance content is extracted from the analytic continuation, including resonance positions and branching ratios, and possible sources of uncertainties are discussed. The results provide the final-state interactions for the ongoing analysis of photo-and electroproduction data.

The ηN final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited ∆ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of E ∼ 2.3 GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions πN → πN , ηN , KΛ and KΣ. For the analysis, the so-called Jülich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. The influence of recent MAMI T and F asymmetry data on the eta photoproduction amplitude is discussed in detail.

The Jülich-Bonn coupled-channel framework is extended to K + Λ photoproduction. The spectrum of nucleon and ∆ resonances is extracted from simultaneous fits to several pion-induced reactions in addition to pion, eta and K + Λ photoproduction off the proton. More than 40,000 data points up to a center-of-mass energy of E ∼ 2.3 GeV including recently measured double-polarization observables are analyzed. The influence of the γp → K + Λ channel on the extracted resonance parameters and the appearance of states not seen in other channels is investigated. The Jülich-Bonn model includes effective three-body channels and guarantees unitarity and analyticity, which is a prerequisite for a reliable determination of the resonance spectrum in terms of poles and residues.

New data on pion-photoproduction off the proton have been included in the partial wave analyses Bonn-Gatchina and SAID and in the dynamical coupled-channel approach Jülich-Bonn. All reproduce the recent new data well: the double polarization data for E, G, H, P and T in γp → π 0 p from ELSA, the beam asymmetry Σ for γp → π 0 p and π + n from Jefferson Laboratory, and the precise new differential cross section and beam asymmetry data Σ for γp → π 0 p from MAMI. The new fit results for the multipoles are compared with predictions not taking into account the new data. The mutual agreement is improved considerably but still far from being perfect.