Abstract
Neutron single particle energies have been measured in using the process. The energies of the resonant states have been deduced to be 4.00(2) MeV and 5.30(4) MeV. The first excited state can be assigned to the single particle state from a comparison with shell model calculations. The measured 4.0 MeV energy difference between the and states gives the size of the shell gap which is in agreement with the recent USD05 (“universal” sd from 2005) shell model calculation, and is large enough to explain the unbound nature of the oxygen isotopes heavier than . The resonance detected at 5.3 MeV can be assigned to a state out of the shell model space. Its energy corresponds to a sized shell gap, therefore, the shell closure disappears at in agreement with Monte Carlo shell model calculations using SDPF-M interaction.
- Received 30 November 2006
DOI:https://doi.org/10.1103/PhysRevLett.98.102502
©2007 American Physical Society