Year: 2026
Type: article
Abstract: Isotonic (constant neutron number) systematics in the deformed rare-earth region have long suggested that nuclei with odd numbers of protons are more compact than their even-proton neighbors-except for Lu, whose recommended nuclear charge radius appeared anomalously large relative to Yb and Hf. We report a high-precision determination of the natural-abundance-averaged Lu-Yb charge-radius difference using extreme-ultraviolet spectroscopy of highly charged Na- and Mg-like ions, supported by high-accuracy relativistic atomic-structure calculations-a recently introduced method with the unique ability to measure inter-element charge-radius differences. Combined with muonic-atom and optical isotope-shift data, our results reestablish a pronounced odd-even staggering along the isotonic chain with neutron number N = 94. Nuclear density functional theory calculations, including quantified uncertainties, fail to reproduce the large stagger, while successfully reproducing the charge-radii staggering along isotopic chains and in semi-magic nuclei. In this work, we resolve the Lu inversion anomaly and provide new constraints for experimental and theoretical studies of nuclear size.
Source: Nature Communications
Authors: E. Takacs, H. Staiger, S. A. Blundell, N. Kimura, H. A. Sakaue, R. F. Garcia Ruiz, W. Nazarewicz, P.-G. Reinhard, C. A. Faiyaz, C. Suzuki, Dipti, I. Angeli, Y. Ralchenko, I. Murakami, D. Kato, Y. Nagai, R. Takaoka, Y. Miya, N. Nakamura
Institutions: National Institute for Fusion Science, Clemson University, Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Grenoble, MIT-Harvard Center for Ultracold Atoms, Massachusetts Institute of Technology, Facility for Rare Isotope Beams, Michigan State University, Friedrich-Alexander-Universität Erlangen-Nürnberg, University of Debrecen, HUN-REN Institute for Nuclear Research, Goddard Space Flight Center, University of Maryland, College Park, Kyushu University, University of Electro-Communications
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
Awards: 重イオン発光の偏光メカニズム：プラズマ偏光分光の深化と相対論的相互作用の物理, G1345504981, THEORETICAL NUCLEAR STRUCTURE, Collaborative Research: PM: High-Z Highly Charged Ions Probing Nuclear Charge Radii, QED, and the Standard Model, G2851952235, G3987901086, Exploring microwave spectroscopy of highly charged ions, G524943974, G6218032654, G6992476341
OpenAlex ID: W7106662010