Search for an s -wave resonance in ⁷Li just above the proton-decay threshold

Near-threshold resonances play an important role in nucleosynthesis and applied nuclear science. The study of nuclei removed from stability has greatly extended the list of resonances close to decay thresholds. The no core shell model with continuum (NCSMC) recently predicted an 𝑠-wave resonance just above the proton-decay threshold of ⁷Li at an excitation energy of 10.2 MeV. This potential case of a near-threshold resonance is dependent on the quantum mechanics of the 𝑝+ ⁶He fragments extended into the continuum. The ⁶He ⁢(𝑑,𝑛)⁢ ⁷Li^* reaction was employed in an attempt to populate this resonance and search for its proton decay via the invariant-mass method. No evidence of this resonance was found. However, the data collected in this search led to better constraints on the energy and width of the isobaric analog state (IAS) with (𝐽^𝜋,𝑇)=(3/2⁻,3/2) and revealed a new weak resonance just above the IAS in energy, predicted by the NCSMC as a (𝐽^𝜋,𝑇)=(3/2⁻,1/2) state and potentially a part of the antianalog structure.