MEASUREMENT OF POLARIZATION OBSERVABLES IN NEUTRAL DOUBLE PION PHOTOPRODUCTION OFF THE PROTON WITH THE CBELSA/TAPS EXPERIMENT

摘要

The Crystal Barrel/TAPS experiment is ideally suited to measure neutral mesons decaying into photons due to its high detection efficiency for photons, good energy resolution, and the nearly complete solid angle coverage. In combination with a longitudinally or transversely polarized target and an energy tagged, linearly or circularly polarized photon beam the experiment allows the measurement of a large set of polarization observables. The presented preliminary results for polarization observables of neutral double pion production obtained with a transversely polarized target show significant deviations from current predictions of partial wave analyses. This clearly indicates that 2π~(0)-photoproduction is not yet understood.