Geometric structure of two-neutron halo nuclei from Efimov physics at the unitary limit

We investigate the geometric structure of two-neutron halo nuclei from the perspective of Efimov physics. Using the analytic three-body wave function obtained from the Faddeev equations in the unitary limit, we explore the connection between Efimov universality and the spatial configuration of these weakly bound systems. The internal geometry is quantified through probability densities, root-mean-square interparticle distances and characteristic opening angles, evaluated for different neutron–core mass ratios. Our results reveal a universal trend in the geometry of s -wave dominated halo nuclei, reflecting the universal correlations characteristic of the Efimov-like regime.