Photoproduction of Mesons off Light Nuclei -- the Search for \eta -Mesic Nuclei

Abstract

Photoproduction of \eta mesons off light nuclei (d, 3He, 7Li) has been measured at the tagged photon beam of the Mainz MAMI accelerator with the combined Crystal Ball/TAPS detection system. Special attention was given to the threshold behavior of the reactions in view of possible indications for the formation of (quasi-) bound \eta -nucleus states, so-called \eta -mesic nuclei. A very strong threshold enhancement of coherent \eta photoproduction off 3He was found and coherent \eta photoproduction off 7Li was observed for the first time. Preliminary results will be discussed.Comment: Invited talk at the International Symposium on Mesic Nuclei, Krakow, 16 June 201