Medium effects to the N(1535) resonance and η mesic nuclei Original Research Article

The structure of η-nucleus bound systems (η mesic nuclei) is investigated as one of the tools to study in-medium properties of the N(1535) (N∗) resonance. We show that, as a general consequence, the η-nucleus potential has a repulsive core at the nuclear center with an attractive part at the nuclear surface, if sufficient reduction of the mass difference of N and N∗ stems from the in-medium effects to N∗. The (d, 3He) spectra are evaluated for the formation of these bound states to investigate the experimental feasibility.