Refined Topology of the N=20 Island of Inversion with High Precision Mass Measurements of ^{31-33}Na and ^{31-35}Mg.

Mass measurements of ^{31-33}Na and ^{31-35}Mg using the TITAN MR-TOF-MS at TRIUMF's ISAC facility are presented, with the uncertainty of the ^{33}Na mass reduced by over 2 orders of magnitude. The excellent performance of the MR-TOF-MS has also allowed the discovery of a millisecond isomer in ^{32}Na. The precision obtained shows that the binding energy of the normally closed N=20 neutron shell reaches a minimum for ^{32}Mg but increases significantly for ^{31}Na, hinting at the possibility of enhanced shell strength toward the unbound ^{28}O. We compare the results with new ab initio predictions that raise intriguing questions of nuclear structure beyond the dripline.

Duke Scholars

Author Jens Dilling Physics