We report on a study of the structure of the unbound nucleus ${}^7\mathrm{He}$ utilizing the proton-removal reaction ${}^2\mathrm{H}({}^8\mathrm{Li},{}^3\mathrm{He}){}^7\mathrm{He}$. Combining the present results with those of our prior measurements of the neutron-adding reaction ${}^2\mathrm{H}({}^6\mathrm{He},p){}^7\mathrm{He}$, a consistent picture emerges for the low-lying excitations in ${}^7\mathrm{He}$. Specifically, the negative-parity sequence of resonances, in order of excitation energies, is consistent with $3/2^{-},1/2^{-}$, and $5/2^{-}$. The stable-beam reactions ${}^2\mathrm{H}({}^7\mathrm{Li},t){}^6\mathrm{Li}$ and ${}^2\mathrm{H}({}^7\mathrm{Li},{}^3\mathrm{He}){}^6\mathrm{He}$ were also measured. The results are compared with the predictions of nuclear structure models, including those of ab initio quantum Monte Carlo calculations.

• Received 30 June 2008

DOI:https://doi.org/10.1103/PhysRevC.78.041302