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.