Abstract
Based on a prior effective Lagrangian model on single pion photoproduction from the nucleon, successfully tested in total and differential cross sections, the helicity dependence from the interaction of circularly polarized photons anda longitudinally polarized nucleon target is studied in the energy range from pi-threshold through the Delta(1232)-resonance region. The doubly polarized total and differential cross section differences for parallel sigma(3/2) and antiparallel sigma(1/2) helicity states are predicted and compared with recent experimental data. We show that the results are sensitive to interferences among different contributions to the process and, thus, represent a complementary test of the theoretical model. A quite satisfactory agreement with recent experimental data from the GDH-collaboration is obtained.