Alpha and helion particle charge radius difference determined from quantum-degenerate helium
Accurate spectroscopic measurements of calculable systems provide a powerful method for testing the Standard Model and extracting fundamental constants. Recently, spectroscopic measurements of finite nuclear size effects in normal and muonic hydrogen resulted in unexpectedly large adjustments of the proton charge radius and the Rydberg constant. We measured the 2<sup>3</sup><i>S</i>→2<sup>1</sup><i>S</i> transition frequency in a Fermi gas of <sup>3</sup>He with an order of magnitude higher accuracy than determined previously. Together with a previous measurement in a <sup>4</sup>He Bose-Einstein condensate, a squared charge radius difference <i>r<sub>h</sub></i><sup>2</sup> - <i>r</i><sub>α</sub><sup>2</sup> = 1.0757(12)<sub>exp</sub>(9)<sub>theo</sub> fm<sup>2</sup> was determined between the helion and alpha particle. This measurement provides a stringent benchmark for nuclear structure calculations.
Authors
- Raphaël Jannin (ORCID: https://orcid.org/0000-0003-4526-7828)
- Hendrick L. Bethlem (ORCID: https://orcid.org/0000-0003-4575-8512)
- Kees Steinebach (ORCID: https://orcid.org/0000-0003-0664-4766)
- K. S. E. Eikema (ORCID: https://orcid.org/0000-0002-2546-3584)
- Yuri van der Werf (ORCID: https://orcid.org/0000-0003-4947-4074)
Institutions
- University of Groningen (NL)
- Advanced Research Center for Nanolithography (Netherlands) (NL)
- Vrije Universiteit Amsterdam (NL)
Publication Details
- Journal
- Science
- Published
- 2025-05-22
- DOI
- https://doi.org/10.1126/science.adj2462
- Citations
- 10
- Primary Topic
- Atomic and Molecular Physics
- Type
- article
- Field-Weighted Citation Impact
- 12.47