Revisiting $\eta'(958)$ nuclear states

Abstract

Observing $\eta'$-nuclear quasibound states requires that the $\eta'$-nuclear potential is both sufficiently attractive and weakly absorptive, as confirmed by the CBELSA/TAPS collaboration analysis of inclusive $\eta'$ production experiments on nuclear targets, including liquid hydrogen (LH$_2$). Here we present an alternative derivation of the $\eta'$-nuclear potential, constrained by near-threshold $pp\to pp\eta'$ and $\gamma p\to\eta' p$ production experiments on a free proton. The resulting $\eta'$-nuclear potential is weakly attractive and strongly absorptive, to the extent that observation of clear signals of $\eta'$-nuclear quasibound states is unlikely. Possible exceptions resulting from the dynamics of the nearby $I=\frac{1}{2}$ $J=({\frac{1}{2}})^-$ nucleon resonance $N^{\ast}$(1895) are briefly discussed.