Recent measurements of nucleon resonance transition form factors with CLAS at Jefferson Lab are discussed. The new data confirm the assertion of the symmetric constituent quark model of the Roper as the first radial excitation of the nucleon. The data on high Q²nπ⁺production better constrain the branching ratios β_Nπand β_Nη. For the first time, the longitudinal transition amplitude to the S₁₁(1535) was extracted from the nπ⁺data. Also, new results on the transition amplitudes for the D₁₃(1520) resonance are presented showing a rapid transition from helicity 3/2 dominance seen at the real photon point to helicty 1/2 dominance at higher Q². I also discuss the status of the search for new excited nucleon states.

The present focus of the CBELSA/TAPS experiment is on meson-photoproduction off the nucleon using polarized photons and polarized targets. Here first preliminary results on the reactions γp→pπ⁰and γp→pη for both circularly and linearly polarized photons and a longitudinally polarized target are presented. Preliminary results for the beam asymmetry ∑ and the double polarization observable G have been extracted for both reactions using the linear polarization data. From the circular polarization data the observable E has been determined. Due to the near 4π angular coverage of the detector system these results cover almost the full solid angle.

We discuss the analysis of data from πN elastic scattering and single pion photo- and electroproduction. The main focus is a study of low-lying non-strange baryon resonances. Here we concentrate on some difficulties associated with resonance identification, in particular the Roper and higher P₁₁states.

The unitary isobar model MAID2007 has been used to analyze the recent data of pion electroproduction. The model contains all four-star resonances in the
region below W=2 GeV and both single-Q²and Q²dependent transition form factors could be obtained for the Delta, Roper, D₁₃(1520), S₁₁(1535), S₃₁(1620), S₁₁(1650), D₁₅(1675), F₁₅(1680) and P₁₃(1720). From the complete world data base, including also π^－data on the neutron, also Q²dependent neutron form factors are obtained. For all transition form factors we also give convenient numerical parameterizations that can be used in other reactions. Furthermore, we show how the transition form factors can be used to obtain empirical transverse charge densities and our first results are given for the Roper, the S₁₁and D₁₃resonances.

We present an overview of a research program for the excited nucleon states in Excited Baryon Analysis Center (EBAC) at Jefferson Lab. Current status of our analysis of the meson production reactions based on the unitary dynamical coupled-channels model is summarized, and the N^*pole positions extracted from the constructed scattering amplitudes are presented. Our plans for future developments are also discussed.

The present status of the Bonn-Gatchina partial wave analysis of the photoproduction and pion induced data is presented. An observation of signals which can be associated with new baryon resonances and possible interpretations of the baryon spectrum is discussed.

We present recent lattice results on the baryon spectrum, nucleon electromagnetic and axial form factors, nucleon to Δ transition form factors as well as the Δ electromagnetic form factors. The masses of the low lying baryons and the nucleon form factors are calculated using two degenerate flavors of twisted mass fermions down to pion mass of about 270 MeV. We compare to the results of other collaborations. The nucleon to Δ transition and Δ form factors are calculated in a hybrid scheme, which uses staggered sea quarks and domain wall valence quarks. The dominant magnetic dipole nucleon to Δ transition form factor is also evaluated using dynamical domain wall fermions. The transverse density distributions of the Δ in the infinite momentum frame are extracted using the form factors determined from lattice QCD.

The paper gives a brief introduction into the COSY-facility, the currently used detector systems (ANKE, TOF and WASA) and the targets (cluster jet, pellet and ABS), and it presents some recent results, which were obtained in the field of
baryon excited states.