Three experiments to search for $T=\frac{3}{2}$ mass-5 analog states have been performed. Both triton energy spectra from the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}\mathrm{}(p,t)\mathrm{}{}_{}{}^5{}_{}{}^{}\mathrm{Li}$ reaction and particle-particle coincidence data on the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}\mathrm{}(p,t)\mathrm{}{}_{}{}^5{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}(p,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^5{}_{}{}^{}\mathrm{He}$ reactions failed to reveal well-defined ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$ or ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ states having expected $T=\frac{3}{2}$ properties. Tentative evidence is found from these measurements for broad $T=\frac{1}{2}$ states at 22-, 25-, and 34-MeV excitation energy. ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ energy spectra from the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}(\alpha ,{}_{}{}^8{}_{}{}^{}\mathrm{B}){}_{}{}^5{}_{}{}^{}\mathrm{H}$ reaction also exhibited no peaks which might be associated with sharp states of ${}_{}{}^5{}_{}{}^{}\mathrm{H}$. These results are qualitatively in agreement with several theoretical predictions that ${}_{}{}^5{}_{}{}^{}\mathrm{H}$ is unbound to particle emission by at least several MeV.

• Received 1 September 1967

DOI:https://doi.org/10.1103/PhysRev.165.1126