Abstract
The first -ray spectroscopy of , with the neutron number , was measured using the one-proton removal reaction at at the RIBF facility. The excitation energy is found at 1656(18) keV, the highest among the Ar isotopes with . This result is the first experimental signature of the persistence of the subshell closure beyond , i.e., below the magic proton number . Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured systematics of neutron-rich Ar isotopes, and support a subshell closure in .
- Received 8 November 2018
- Revised 22 January 2019
DOI:https://doi.org/10.1103/PhysRevLett.122.072502
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society