Summit of the N=40 island of inversion: Precision mass measurements and ab initio calculations of neutron-rich chromium isotopes

• Published in: Physics letters. B Vol. 833; p. 137288
• Main Authors: Silwal, R., Andreoiu, C., Ashrafkhani, B., Bergmann, J., Brunner, T., Cardona, J., Dietrich, K., Dunling, E., Gwinner, G., Hockenbery, Z., Holt, J.D., Izzo, C., Jacobs, A., Javaji, A., Kootte, B., Lan, Y., Lunney, D., Lykiardopoulou, E.M., Miyagi, T., Mougeot, M., Mukul, I., Murböck, T., Porter, W.S., Reiter, M., Ringuette, J., Dilling, J., Kwiatkowski, A.A.
• Format: Journal Article
• Language: English
• Published: Elsevier 10-10-2022
• Subjects: Intruder configuration; Island of inversion; Mass measurement; MR-TOF-MS; Nuclear structure; Two neutron separation energies
• ISSN: 0370-2693
• DOI: 10.1016/j.physletb.2022.137288

Mass measurements continue to provide invaluable information for elucidating nuclear structure and scenarios of astrophysical interest. The transition region between the Z=20 and 28 proton shell closures is particularly interesting due to the onset and evolution of nuclear deformation as nuclei become more neutron-rich. This provides a critical testing ground for emerging ab-initio nuclear structure models. Here, we present high-precision mass measurements of neutron-rich chromium isotopes using the sensitive electrostatic Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) at TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) facility. Our high-precision mass measurements of 59,61−63Cr confirm previous results, and the improved precision in measurements of 64−65Cr refine the mass surface beyond N=40. With the ab initio in-medium similarity renormalization group, we examine the trends in collectivity in chromium isotopes and give a complete picture of the N=40 island of inversion from calcium to nickel.