Abstract
We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei , , and as well as that of . In addition, the most precise determinations to date for and are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in , with a dominant configuration, and a single-neutron halo in with the valence neutron occupying predominantly the orbital. Despite a very low two-neutron separation energy the development of a halo in is hindered by the character of the valence neutrons.
- Received 1 March 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.202503
© 2012 American Physical Society