Investigation of the $\eta'N$ system using the linear sigma model
  In this paper, we investigate the $\eta'N$ system using the three-flavor linear sigma model including the effect of flavor SU(3) symmetry breaking. The $\eta'N$ bound state is also found in the case including flavor symmetry breaking and coupling with the $\eta N$ and $\pi N$ channels. The $\eta'N$ interaction becomes more attractive with the inclusion of flavor symmetry breaking, which causes mixing between the singlet and octet scalar mesons. The existence of such a bound state would have some impact on the $\eta'$-nucleus system, which is of interest from both theoretical and experimental viewpoints. 
Shuntaro Sakai and Daisuke Jido
nucl-th hep-ph