Work

Alpha and helion particle charge radius difference determined from quantum-degenerate helium

Year: 2025

Type: article

Abstract: 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 3 S →2 1 S transition frequency in a Fermi gas of 3 He with an order of magnitude higher accuracy than determined previously. Together with a previous measurement in a 4 He Bose-Einstein condensate, a squared charge radius difference r h 2 – r α 2 = 1.0757(12) exp (9) theo fm 2 was determined between the helion and alpha particle. This measurement provides a stringent benchmark for nuclear structure calculations.

Source: Science

DOI: 10.1126/science.adj2462

Authors: Y. van der Werf, K. Steinebach, R. Jannin, H. L. Bethlem, K. S. E. Eikema

Institutions: Vrije Universiteit Amsterdam, University of Groningen, Advanced Research Center for Nanolithography (Netherlands)

Language: English

Topic: Atomic and Molecular Physics

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funder: Nederlandse Organisatie voor Wetenschappelijk Onderzoek

Award: Probing new physics with ultracold helium atoms