Helicity amplitudes of nonstrange baryons in the third and fourth resonance region

Baryon resonances with masses around 1600 MeV and higher come into play already at threshold in meson photo- and electroproduction reactions from the proton such as p(γ (*), ππ)N, p(γ (*), K)Y, p(γ (*), ω)p and p(γ (*), η)p. We present results for the Q 2 dependence of the helicity amplitudes of these nonstrange baryons resonances, computed in the framework of the Bethe-Salpeter model developed by the Bonn group. The model describes bound states of three relativistic constituent quarks, interacting through an instantaneous linear confining potential and a residual instanton-induced interaction potential. The seven model parameters were fitted to the best known baryon masses, but no extra parameters are introduced in computing the helicity amplitudes.