Speaker
Description
A large mass reduction of the η′(958) in nuclei is expected in several theoretical models. If there is large mass reduction, an η′ meson and a nucleus can form a bound state. We investigated the η′-nucleus system in the LEPS2/BGOegg experiment. To search for the η′-nucleus bound state, we carried out the missing mass spectroscopy of the 12C(γ,p) reaction. To suppress background events from mult-meson productions, the one nucleon absorption decay products were simultaneously measured for the first time. In addition, we also carried out the simultaneous measurement of escaping η′ mesons from nuclei. We will report the η′-nucleus optical potential evaluated by using both data. We will also show the preliminary results of the direct measurement of η′ mass spectra from the η′→γγ decay in nuclei.
