Erlangen 2022 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 20: Precision spectroscopy of atoms and ions (joint session A/Q)
A 20.12: Poster
Mittwoch, 16. März 2022, 16:30–18:30, P
Two-loop self-energy corrections to the bound-electron g-factor: M-term — •Bastian Sikora1, Vladimir A. Yerokhin2, Christoph H. Keitel1, and Zoltán Harman1 — 1Max-Planck-Institut für Kernphysik, Heidelberg, Germany — 2Center for Advanced Studies, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
The theoretical uncertainty of the bound-electron g-factor in heavy hydrogenlike ions is dominated by uncalculated two-loop Feynman diagrams. Due to the presence of ultraviolet divergences, diagrams with two self-energy loops need to be split into the loop-after-loop (LAL) contribution and the so-called F-, M- and P-terms which require different numerical techniques. In our previous work, we have obtained full results for LAL and the F-term [1].
In this work, we present our results for the M-term contribution. This corresponds to the ultraviolet finite part of nested and overlapping loop diagrams in which the Coulomb interaction in intermediate states is taken into account exactly.
Our results are highly relevant for ongoing and future experiments with high-Z ions as well as for an independent determination of the fine-structure constant α from the bound-electron g-factor [2].
[1] B. Sikora, V. A. Yerokhin, N. S. Oreshkina, et al., Phys. Rev. Research 2, 012002(R) (2020).
[2] S. Sturm, I. Arapoglou, A. Egl, et al., EPJ ST 227, 1425 (2019)