Abstract
The very neutron-rich oxygen isotopes O and O are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F and F at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O plus one or two neutrons, the O ground-state energy and width are determined, and upper limits for the O ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon () forces, including for the first time residual forces, which are shown to be amplified as valence neutrons are added.
1 More- Received 2 September 2012
DOI:https://doi.org/10.1103/PhysRevC.88.034313
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