Near-Threshold Production of η-Mesons

It is shown that the striking energy variation in the $p\, d \rightarrow \mbox{$^{\, 3}{\rm He}$}\, \eta$ cross section near threshold is probably due to a final state interaction associated with a large (complex) $\eta -\mbox{$^{3}{\rm He}$}$ scattering length. The consequences of this hypothesis are studied for the production of the meson in the $\eta -\mbox{$^{4}{\rm He}$}$ and $\eta -\mbox{$^{7}{\rm Be}$}$ channels.