Electromagnetic moments of the odd-mass nickel isotopes \(^{59-67}\)Ni

• Published in: arXiv.org 2024-05
• Main Authors: Müller, P, Kaufmann, S, Miyagi, T, Billowes, J, Bissell, M L, Blaum, K, Cheal, B, Garcia Ruiz, R F, Gins, W, Gorges, C, Heylen, H, Kanellakopoulos, A, Malbrunot-Ettenauer, S, Neugart, R, Neyens, G, Nörtershäuser, W, Ratajczyk, T, Rodríguez, L V, Sánchez, R, Sailer, S, Schwenk, A, Wehner, L, Wraith, C, Xie, L, Xu, Z Y, Yang, X F, Yordanov, D T
• Format: Article
• Language: English
• Subjects: Angular momentum; Magnetic dipoles; Magnetic moments; Nickel isotopes; Quadrupoles
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2405.13668

The magnetic dipole and the spectroscopic quadrupole moments of the nuclear ground states in the odd-mass nickel isotopes \(^{59-67}\)Ni have been determined using collinear laser spectroscopy at the CERN-ISOLDE facility. They are compared to ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) calculations including contributions of two-body currents as well as to shell-model calculations. The two-body-current contributions significantly improve the agreement with experimental data, reducing the mean-square deviation from the experimental moments by a factor of 3 to 5, depending on the employed interaction. For all interactions, the largest contributions are obtained for the \(5/2^-\) (\(7/2^-\)) isotopes \(^{65}\)Ni (\(^{55}\)Ni), which is ascribed to the high angular momentum of the \(f\) orbitals. Our results demonstrate that the inclusion of two-body-current contributions to the magnetic moment in an isotopic chain of complex nuclei can be handled by the VS-IMSRG and can outperform phenomenological shell-model calculations using effective \(g\)-factors in the nickel region.