Search for Bound States of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>η</mml:mi></mml:math>Meson in Light Nuclei

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 $3\ensuremath{\sigma}(P&gt;0.9987)$.