Speaker
Description
When coming close to an atom, a muon can be captured by the nucleus and form a hydrogen-like
muonic ion, which is typically also surrounded by atomic electrons. This atomic system is commonly
referred to as a muonic atom. Due to the muon’s high mass, it is located much closer to the nucleus;
and, especially for heavy nuclei, this results in big nuclear size effects and a strong dependence of
the muon bound-state energies on the nuclear charge and current distributions, as well as in large
relativistic effects [1, 2]. A combination of the knowledge about the level structure and experiments
measuring the transition energies in muonic atoms enabled the determination of nuclear parameters
like charge radii, electric quadrupole and magnetic dipole moments [3].
Theoretical predictions of the fine-, hyperfine structure, and dynamical splitting of muonic atoms,
based on rigorous QED calculations will be presented. State-of-the-art techniques from both nuclear
and atomic physics are brought together in order to perform the most comprehensive to date
calculations of the quantum-electrodynamics and nuclear contributions. A long-standing problem of
fine-structure anomalies in muonic atoms will be revisited in the light of the last improvements on
nuclear-polarization [4] and self-energy calculations [5].
Finally, we will discuss the currently used tabulated values of the rms radii based on their extraction
from the muonic spectra and possible further development in this direction.
References
[1] A. Antognini et al., Phys. Rev. C 101, 054313 (2020)
[2] N. Michel, N. S. Oreshkina, and C. H. Keitel, Phys. Rev. A 96, 032510 (2017)
[3] N. Michel and N. S. Oreshkina, Phys. Rev. A 99, 042501 (2019)
[4] I. A. Valuev, G. Col`o, X. Roca-Maza, C. H. Keitel, and N. S. Oreshkina, Phys. Rev. Lett. 128,
203001 (2022)
[5] N. S. Oreshkina, https://arxiv.org/abs/2206.01006 (2022)
