Muonic-Atom Spectroscopy and Impact on Nuclear Structure and Precision QED Theory

TL;DR

Advances in muonic atom spectroscopy are enhancing our understanding of nuclear structure, fundamental constants, and QED, with potential for high-precision measurements and testing theoretical models across atomic and nuclear physics.

Contribution

This paper reviews recent progress and future prospects in muonic atom spectroscopy, highlighting its impact on nuclear structure, fundamental constants, and tests of quantum electrodynamics.

Findings

Improved measurements of hyperfine splitting and Lamb shift in muonic hydrogen.

Potential to refine charge radii of light nuclei in the Z=3-8 range.

Upcoming experiments will test ab-initio nuclear theories and bound-state QED.

Abstract

Recent progress in laser and x-ray spectroscopy of muonic atoms offers promising long-term possibilities at the intersection of atomic, nuclear and particle physics. In muonic hydrogen, laser spectroscopy measurements will determine the ground-state hyperfine splitting (HFS) and additionally improve the Lamb shift by a factor of 5. Precision spectroscopy with cryogenic microcalorimeters has the potential to significantly improve the charge radii of the light nuclei in the $Z=3-8$ range. Complementary progress in precision should be achieved on the theory of nucleon- and nuclear-structure effects. The impact of this muonic-atom spectroscopy program will be amplified by the upcoming results from H and He$^+$ spectroscopy, simple molecules such as HD$^+$ and Penning trap measurements. In this broader context, one can test ab-initio nuclear theories, bound-state QED for two- or three-body systems, and determine fundamental constants, such as the Rydberg ($R_\infty$) and the fine-structure ($\alpha$) constants.