Search for Bound States of theηMeson in Light Nuclei

Abstract

A search for nuclear-bound states of the $\ensuremath{\eta}$ meson has been carried out. Targets of lithium, carbon, oxygen, and aluminum were placed in a ${\ensuremath{\pi}}^{+}$ beam at 800 MeV/c. A predicted $\ensuremath{\eta}$ bound state in $^{15}\mathrm{O}^{*}({E}_{x}\ensuremath{\approx}540 \mathrm{MeV})$ with a width of \ensuremath{\cong} 9 MeV was not observed. A bound state of a size ⅓ of the predicted cross section would have been seen in this experiment at a confidence level of $3\ensuremath{\sigma}(P>0.9987)$.