Speaker
Description
In recent years, a new generation of photoproduction experiments measuring not only cross sections but also single and double polarization asymmetries has helped the partial wave analysis groups to provide much more stringent information about the involed reaction multipoles and thus the contributing nucleon resonances. However, almost all existing measurements were obtained using proton targets. Data on reactions off the neutron are scarce and mostly limited to unpolarized cross sections and only a few single polarization asymmetries.
New experiments at the electron stretcher accelerator ELSA in Bonn, with the Crystal Barrel/TAPS detector setup and a transversely polarized deuterated butanol target, allowed for the simultaneous measurement of the polarization observables $\Sigma$, T, P, and H off protons and neutrons. The data are of particular relevance for clarifying the origin of the narrow structure in the $\eta n$ system at W = 1.66 GeV.
In this talk, recent results on exclusive $\pi^0$ and $\eta$ photoproduction off quasi-free neutrons and their interpretation within the BnGa PWA are discussed.
