$η$ and $η'$ mesons in nuclear matter and nuclei

Abstract: We present updated and extended results for the $\eta$- and $\eta'$-nucleus bound state energies, obtained by solving the Schr\"{o}dinger and Klein-Gordon equations with complex optical potentials, for a wide range of nuclei. The $\eta$ and $\eta'$ nuclear potentials are obtained in the local density approximation from the mass shift of these mesons in nuclear matter, which is calculated within the quark-meson coupling model. Our results show that the $\eta$ and $\eta'$ mesons are expected to form mesic nuclei with all the nuclei considered. However, the signal for the formation of the $\eta$- and $\eta'$-mesic nuclei may be difficult to identify experimentally due to possible large widths.