Abstract
We present results from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. We report the first mass measurements of and and find atomic mass excesses of and , respectively. These masses provide strong evidence for the closed shell nature of neutron number in argon, which is therefore the lowest even- element exhibiting the closed shell. The resulting trend in binding-energy differences, which probes the strength of the shell, compares favorably with shell-model calculations in the - shell using SDPF-U and SDPF-MU Hamiltonians.
- Received 27 October 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.022501
© 2015 American Physical Society