Authors: Y. van der Werf, K. Steinebach, R. Jannin, H. L. Bethlem, K. S. E. Eikema
Published: 2025-05-23
Source: Full article
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