η-PHOTOPRODUCTION OFF ³He: SEARCH FOR η-MESIC NUCLEI

Abstract

Photoproduction of η-mesons off 3 He has been studied via the η → 2γ and η → 3π0 decay modes at the tagged photon beam of the Mainz MAMI accelerator using the combined 4π Crystal Ball/TAPS calorimeter. The main motivation for this experiment was the search for η-mesic nuclei. A possible signature for such states is a threshold enhancement of coherent η-photoproduction similar to what has been observed in hadronic induced reactions at COSY.8