Near-Threshold Production of $\eta$-Mesons

Abstract

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.

Comments: 9 pages + 2 postscript figures