Abstract
We report high-precision mass measurements of isotopes performed at the LEBIT facility at NSCL and at the TITAN facility at TRIUMF. Our results provide a substantial reduction of their uncertainties and indicate significant deviations, up to 0.7 MeV, from the previously recommended mass values for . The results of this work provide an important update to the description of emerging closed-shell phenomena at neutron numbers and above proton-magic . In particular, they finally enable a complete and precise characterization of the trends in ground state binding energies along the isotone, confirming that the empirical neutron shell gap energies peak at the doubly magic . Moreover, our data, combined with other recent measurements, do not support the existence of a closed neutron shell in at . The results were compared to predictions from both ab initio and phenomenological nuclear theories, which all had success describing neutron shell gap energies but were highly disparate in the description of the isotone.
- Received 1 June 2020
- Revised 28 September 2020
- Accepted 14 December 2020
DOI:https://doi.org/10.1103/PhysRevLett.126.042501
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