Univ.-Prof.Dr.Michael Ostrick

My research focuses on the structure of protons and neutrons, the building blocks of atomic nuclei. A photon incident on a proton or a neutron causes a polarization or excitation of the nucleon if the wavelength is sufficiently small. Similar phenomena at much larger length scales are well known in optics and atomic physics, when visible light interacts with matter. In contrast to such atomic systems, we have only a poor understanding of the mechanisms responsible for the formation of nucleon excitions and even the empirical knowledge about the mass spectrum of light hadrons is rather limited. Photoinduced mesons production and Compton scattering on nucleons are powerfull tools to study nucleon resonances and poalrizabilities. Presently new experiemts are performed at the photon beam facilities A2 at MAMI and Crystal-Barrel at ELSA. Hadron structure and spectroscopy with high-energy muon and hadron beams are key aspects of the COMPASS experiment at CERN.