Search for mesic nuclei in the photoproduction of ηπ~0 mesons off light nuclei

摘要

For the understanding of the strong nuclear force, the study of interaction between mesons and nuclei is important. In case of long lived charged mesons, like π and K, secondary beams can be used for experiments. But the situation is different for the short lived neutral mesons, like π~0, η and η'. The only access is indirect, making use of final-state interaction (FSI). The mesons are produced with some initial reaction in the nucleus and then their interaction with the same nucleus is studied. It is much discussed whether it is possible to form, via the strong interaction, quasi-bound states of mesons and nuclei, which would be the ideal tool for such studies. We will present preliminary results from the Crystal Ball/TAPS experiment at the Mainz MAMI accelerator for double neutral meson photoproduction, showing interesting potential to study meson nucleon interaction and discuss their relevance. The very first attempt has been made to measure the quasi-free behavior of the photoproduction of ηπ~0 mesons from the ~2 H.