Sprecher
Beschreibung
The theoretical uncertainty of the bound-electron
Due to the presence of ultraviolet divergences, two-loop self-energy Feynman diagrams need to be split into the loop-after-loop (LAL) contribution and the so-called F-, M- and P-terms which require different analytical and numerical techniques. The F-term corresponds to the ultraviolet divergent part of the nested and overlapping loop diagrams with free electron propagators inside the self-energy loops. The M-term 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. In our previous work, we have obtained full results for LAL and the F-term [4]. In this work, we present our results for the M-term contribution. P-term contributions correspond to diagrams which contain both bound-electron propagators inside the self-energy loops as well as an ultraviolet subdiagram and will be considered in a future work.
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[2] S. Sturm, I. Arapoglou, A. Egl, et al., Eur. Phys. J.: Spec. Top. 227:1425 (2019).
[3] V. Debierre, C. H. Keitel and Z. Harman., Phys. Lett. B 807:135527 (2020).
[4] B. Sikora, V. A. Yerokhin, N. S. Oreshkina, et al., Phys. Rev. Research 2:012002(R) (2020).