Year: 2026
Type: article
Abstract: The $2p\to1s$ transition energy in muonic $^9$Be was measured using a metallic magnetic calorimeter, resulting in $E_{2p\to 1s}=33\,391.48(34)\,$eV. The result is 30 times more precise than the previous best measurement and enables the extraction of the corresponding nuclear charge radius $r_c($$^9$Be$)=2.5506(51)\,$fm. It is $2.4$ times more precise than the commonly used value based on electron scattering and differs from it by $2.3$ times the combined uncertainties. This measurement represents the first determination of a nuclear charge radius using muonic x-ray spectroscopy with microcalorimeters.
Source: Physical Review Letters
DOI: 10.1103/l26q-678g
Authors: Ofir Eizenberg, Shikha Rathi, Andreas Abeln, Sonia Bacca, Gonçalo Baptista, Nir Barnea, Noam Burger, Thomas Elias Cocolios, Marie Deseyn, Tim Egert, Christian Enss, Andreas Fleischmann, Loredana Gastaldo, César Godinho, Nitzan Goldberg, Michael Heines, Daniel Hengstler, Paul Indelicato, Weiguang Jiang, Klaus Kirch, Andreas Knecht, Daniel Kreuzberger, Jorge Machado, Ulf-G. Meißner, Ben Ohayon, Nancy Paul, Randolf Pohl, Tim Redelbach, Michael Roosa, Katharina von Schoeler, Quentin Senetaire, Shihang Shen, Daniel Unger, Stergiani Marina Vogiatzi, Johanna Walch, Frederik Wauters, Aziza Zendour
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7169188491