ec 2 00 3 Three - body structure of the low - lying 17 Ne - states

The Borromean nucleus 17Ne (15O+p+ p) is investigated by using the hyperspheric adiabatic expansion for a a three-body system. The measured size of 15O and the low-lying resonances of 16F (15O+p) are first used as constraints to determine both central and spin-dependent two-body interactions. Then, the ground state structure of 17Ne is found to be an almost equal mixture of s2 and d2 proton-15O relative states, the two lowest excited states have about 80% of sd-mixed components, and for the next two excited three-body states the proton-15O relative s-states do not contribute. The spatial extension is as in ordinary nuclei. The widths of the resonances are estimated by the WKB transmission through the adiabatic potentials and found in agreement with the established experimental limits. We compare with experimental information and previous works. PACS: 21.45.+v, 27.20.+n, 21.10.Dr