Year: 2026
Type: preprint
Abstract: Mass measurements of the ground and isomeric states of $^{68-70}$Co have been performed using the JYFLTRAP Penning-trap mass spectrometer at the IGISOL facility. The masses were measured, either for the first time for the isomeric states of $^{68}$Co and $^{70}$Co, or with greatly improved precision for the others, removing ambiguities in the mass surface beyond $N=40$. The ordering of the low and high-spin states in $^{68}$Co and $^{70}$Co has also been established. The results, supported by Large-Scale Shell Model and Discrete Non-Orthogonal Shell-Model calculations, show a gradual lowering of intruder states with increasing neutron number, eventually leading to an inversion in $^{70}$Co. These findings clarify previously proposed contradictory interpretations. Finally, we demonstrate the importance of including induced effective 3N forces for a consistent description of binding energies in the island of inversion near $N=40$.
Source: arXiv (Cornell University)
Institutions: Centre National de la Recherche Scientifique, Université de Bordeaux, Laboratoire de Physique des deux infinis Bordeaux, Institut National de Physique Nucléaire et de Physique des Particules, Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, École Nationale Supérieure d'Ingénieurs de Caen, Laboratoire de Physique Corpusculaire de Caen, Université de Caen Normandie, Belgian Nuclear Research Centre, Grand Accélérateur National d'Ions Lourds, University of Jyväskylä
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212255096