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

• 成果类型: Article
• 署名作者: van der Werf, Y.; Steinebach, K.; Jannin, R.; Bethlem, H. L.; Eikema, K. S. E.
• 署名单位: Vrije Universiteit Amsterdam; University of Groningen; Eindhoven University of Technology; Universite Paris Saclay; Centre National de la Recherche Scientifique (CNRS)
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8674
• DOI: 10.1126/science.adj2462
• 发表日期: 2025-05-22
• 页码: 850-853
• 关键词: spectroscopy; size

摘要

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 He-3 with an order of magnitude higher accuracy than determined previously. Together with a previous measurement in a He-4 Bose-Einstein condensate, a squared charge radius difference r(h)(2) - r(alpha)(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.