New Angular Correlation Measurements of Continuum-Coupled Particle-Unbound Superradiant Nuclear States

There is now a community-wide push in nuclear physics away from isotopic stability toward the nucleon driplines and the continuum beyond. As modern accelerator facilities grant access to nuclei near the driplines, it becomes necessary to study the effect of the continuum on nuclear excitations. New angular correlations of the ¹²C(³He,dp)¹²C reaction have been measured using the SE-SPS (Super-Enge Split-Pole Spectrograph) at FSU and a new silicon barrel array. Coupled asymmetric decay patterns from both the sharp low-lying doublet and the broad high-lying superradiant state of ¹³N have been observed and analyzed in the coupled-channels-fed grand density matrix formalism (CC-GDM). It will be shown that the CC-GDM method works well to study the structure of sharp, long-lived unbound states, but requires more complex hypotheses to describe the unexpected decay patterns of states with strong continuum coupling and short lifetimes.