The helion charge radius from laser spectroscopy of muonic helium-3 ions
Hydrogen-like light muonic ions, in which one negative muon replaces all of the electrons, are extremely sensitive probes of nuclear structure. Using pulsed laser spectroscopy, we have measured three 2<i>S</i>-2<i>P</i> transitions in the muonic helium-3 (μ<sup>3</sup>He<sup>+</sup>) ion, an ion formed by a negative muon and bare helium-3 nucleus. This allowed us to extract the Lamb shift, the 2<i>P</i> fine structure splitting, and the 2<i>S</i>-hyperfine splitting in μ<sup>3</sup>He<sup>+</sup>. Comparing these measurements with theory, we determined the root-mean-square charge radius of the helion (<sup>3</sup>He nucleus) to be <i>r<sub>h</sub></i> = 1.97007(94) fm, in good agreement with the value from elastic electron scattering but a factor 15 more accurate. Our results represent benchmarks for few-nucleon theories and open the way for precision quantum electrodynamics tests in He atoms and ions.
Authors
- F. Kottmann (ORCID: https://orcid.org/0000-0002-4668-7456)
- Aldo Antognini (ORCID: https://orcid.org/0000-0002-1837-0419)
- Andreas Voß (ORCID: https://orcid.org/0009-0005-1180-2839)
- Jorge Machado (ORCID: https://orcid.org/0000-0002-0383-4882)
- D. S. Covita
- F. Nez (ORCID: https://orcid.org/0000-0002-3478-7521)
- Marwan Abdou Ahmed (ORCID: https://orcid.org/0000-0002-1064-9298)
- Birgit Weichelt
- F. Mulhauser (ORCID: https://orcid.org/0000-0003-2429-3314)
- K. Kirch (ORCID: https://orcid.org/0000-0002-1720-7636)
- A. Knecht (ORCID: https://orcid.org/0000-0002-3767-950X)
- Julian J. Krauth (ORCID: https://orcid.org/0000-0001-7769-650X)
- Pedro Amaro (ORCID: https://orcid.org/0000-0002-5257-6728)
- J.F.C.A. Veloso (ORCID: https://orcid.org/0000-0002-7107-7203)
- Thomas Graf (ORCID: https://orcid.org/0000-0002-8466-073X)
- M. Hildebrandt (ORCID: https://orcid.org/0000-0002-9425-5543)
- Csilla I. Szabo (ORCID: https://orcid.org/0000-0002-6125-7948)
- Sandrine Galtier (ORCID: https://orcid.org/0000-0001-8153-102X)
- Karsten Schuhmann (ORCID: https://orcid.org/0009-0002-4378-7862)
- Yiwei Liu (ORCID: https://orcid.org/0000-0002-1090-0665)
- Boris Naar (ORCID: https://orcid.org/0000-0003-4381-4461)
- L. Julién (ORCID: https://orcid.org/0000-0001-7010-8314)
- Randolf Pohl (ORCID: https://orcid.org/0000-0001-6435-659X)
- J.M.F. dos Santos (ORCID: https://orcid.org/0000-0002-8841-6523)
- Marc Diepold
- C. M. B. Monteiro (ORCID: https://orcid.org/0000-0002-1912-2804)
- F. D. Amaro (ORCID: https://orcid.org/0000-0001-7315-0550)
- L. M. P. Fernandes (ORCID: https://orcid.org/0000-0002-7061-8768)
- J. P. Santos (ORCID: https://orcid.org/0000-0002-5890-0971)
- P. Indelicato (ORCID: https://orcid.org/0000-0003-4668-8958)
- B. Franke (ORCID: https://orcid.org/0000-0001-8417-4603)
- Johannes Götzfried
- Tzu-Ling Chen (ORCID: https://orcid.org/0000-0002-2243-5780)
- D. Taqqu (ORCID: https://orcid.org/0000-0001-9707-7490)
- T. W. Hänsch
- F. Biraben
- Andrea L. Gouvea (ORCID: https://orcid.org/0000-0002-2674-8733)
- Tobias Nebel
- A. Dax (ORCID: https://orcid.org/0000-0002-4788-2632)
Institutions
- University of Stuttgart (DE)
- Centre National de la Recherche Scientifique (FR)
- Johannes Gutenberg University Mainz (DE)
- National Tsing Hua University (TW)
- Laboratoire Kastler Brossel (FR)
- École Normale Supérieure - PSL (FR)
- ETH Zurich (CH)
- Sorbonne Université (FR)
- Max Planck Institute of Quantum Optics (DE)
- University of Aveiro (PT)
- University of Coimbra (PT)
- Ludwig-Maximilians-Universität München (DE)
- Universidade Nova de Lisboa (PT)
Publication Details
- Journal
- Science
- Published
- 2025-05-22
- DOI
- https://doi.org/10.1126/science.adj2610
- Citations
- 15
- Primary Topic
- Atomic and Molecular Physics
- Type
- article
- Field-Weighted Citation Impact
- 18.70