Unbound nuclei studied by projectile fragmentation

The level ordering in the unbound nucleus 13Be is firmly established by using a time-dependent projectile fragmentation model, comparing to experimental data and using structure inputs obtained from a semi-phenomenological core-vibration coupling model of two-neutron halo nuclei. Thus, from the shell ordering, the neutron–core interaction is determined, which is needed by any three-body model of Borromean nuclei. As a consistency test, we show that the energy spectra of some beryllium isotopes obtained using the particle–particle random phase approximation predict the same shell ordering as those extracted from the reaction model versus data analysis.