Photoproduction of neutral mesons in the first and second resonance region

The results from a series of experiments investigating pi(0)- and eta-photoproduction are summarized. They were carried out with the TAPS detector at the Mainz MAMI accelerator. The p(gamma,eta)p reaction was used to study the excitation of the S-11(1535) on the free nucleon. Quasifree eta-photoproduction on deuterium was explored for a comparison of the p(gamma,eta)p and n(gamma,eta)n cross sections. These data together with an upper limit for the d(gamma,eta)d reaction allowed a determination of the electromagnetic helicity amplitudes of the S-11 -< N transition. Quasifree eta-photoproduction on nuclei was used for a study of eta nucleus final state interactions and the excitation of the S-11(1535) resonance in the nuclear medium. Finally a comparison of free and quasifree pi(0)-production from the proton, the deuteron and from C-12 shows a strong suppression of the resonance structure for nuclear targets.