Abstract
The structure of deformed neutron-rich nuclei in the rare-earth region is of significant interest for both the astrophysics and nuclear structure fields. At present, a complete explanation for the observed peak in the elemental abundances at eludes astrophysicists, and models depend on accurate quantities, such as masses, lifetimes, and branching ratios of deformed neutron-rich nuclei in this region. Unusual nuclear structure effects are also observed, such as the unexpectedly low energies of the first levels in some even-even nuclei at . In order to address these issues, mass and -decay spectroscopy measurements of the and nuclei were performed at the Californium Rare Isotope Breeder Upgrade radioactive beam facility at Argonne National Laboratory. Evidence for a gap in the single-particle neutron energies at and for large deformation () is discussed in relation to the unusual phenomena observed at this neutron number.
- Received 19 January 2018
- Revised 27 March 2018
DOI:https://doi.org/10.1103/PhysRevLett.120.182502
© 2018 American Physical Society