Studying the Proton-Unbound Superradiant State in ¹³C

This work continues the efforts at FSU’s John D. Fox Accelerator Laboratory to study nuclear structure of states embedded in the continuum. Two energy and spin-degenerate states in ¹³C exhibit the phenomena of “superradiance” where one state couples to the continuum while the other is sapped of its width (trapped state). A campaign to investigate these states was conducted in June 2025. The first reaction, ¹²C(d,p)¹³C, was used to study the superradiant state that manifests as a broad (1.5 MeV wide) continuous peak at 8.20 MeV. The second reaction, ⁹Be(⁶Li, d)¹³C, was utilized to study the alpha-transfer strength of both the 7.68 MeV trapped state and the 8.20 MeV superradiant state. Reaction products were measured using Fox Lab’s Super-Enge Split-Pole Spectrograph (SE-SPS), with beam energies of E(d) = 16 MeV, and E(⁶Li) = 32 MeV respectively. Results from these experiments will be presented.