Deformation, halo, and bubble structure: A paradigm shift of exotic phenomena in light to medium mass nuclei

Abstract

The emergence of exotic nuclear structures, such as deformation, one- and two-neutron halos, and bubble configurations, marks a paradigm shift in our understanding of light- to medium-mass nuclei far from stability, particularly near and within the island of inversion extending across $N=20-28$. In this review, we integrate microscopic structure calculations using the antisymmetrized molecular dynamics method with reaction theories such as the Glauber model for high-energy collisions, and highlight the use of the fully quantum mechanical finite-range distorted wave Born approximation for calculating both inclusive and exclusive Coulomb breakup observables for these medium mass systems. These theoretical frameworks enable precise probing of nuclear density profiles through observables such as total reaction cross sections, neutron removal cross sections, relative energy spectra, parallel momentum distributions, and angular distributions. Applications to several nuclei in the island of inversion reveal enhanced halo extensions, neutron-neutron correlations in Borromean nuclei, and central density depletions in bubbles, challenging traditional shell-model paradigms. Furthermore, the sensitivity of astrophysical reaction rates to these exotic inputs is explored, demonstrating their role in the refinement of r-process nucleosynthesis models and elemental abundance predictions. This unified approach not only bridges nuclear structure and reactions, but also highlights the driplines as frontiers for unraveling nuclear matter under extreme conditions, with implications for rare-isotope beam experiments and beyond.