Theoretische Untersuchungen zur Asymmetrie der Pionphotoproduktion mit einem polarisierten Target

The theoretical importance of experiments with polarised targets for pion photoproduction at high energies is discussed. In an introductory chapter the basic formulas and simple Regge pole models are introduced in connection with elastic pion‐proton scattering. The relevance of Regge‐cut models is considered in connection with pion‐charge‐exchange scattering. In the main part we write down formulas for the polarisation parameters in terms of the helicity amplitudes for pion photoproduction. Then we concentrate on the target asymmetry A for photoproduction of neutral and charged pions. Several models with Regge poles and Regge cuts generated by absorption are presented and discussed concerning the results for A . In the last part we report a fit to π ± photoproduction data and give predictions of A for γp → π + n and γn → π−p.