Halo Phenomena in Light- to Medium-Mass Nuclei with Three-Body Models

Short-lived nuclear systems with light to medium masses are showing halo phenomena in regions of the nuclear chart that were still unexplored when halo nuclei were discovered 40 years ago. We study these exotic systems with three-body models, including nucleon–nucleon correlations, with the aim of reproducing measurable properties like radii and electromagnetic transition strengths. On the nucleon-rich side, drip-line fluorine isotopes are showing clear signs of a halo structure. Recently, we proposed that F29 is a moderate two-neutron halo nucleus with a large radius and a strong B(E1) response to the continuum. The three-body model places it at the borders of the island of inversion, which is corroborated by new data. According to our models, the next interesting isotope, F31, also has large spatial extension due to p-wave components and enhanced B(E1) response, pointing to a speculative halo structure. On the proton-rich side, we have studied the Sb102 system, composed of a Sn100 core plus a proton–neutron-correlated subsystem. We find that the weakening of the proton–neutron correlations with respect to the bare deuteron indicates that this is a one-proton emitter. We propose that the presence of a resonant state and its decay might provide a crucial benchmark for this system.