A phenomenological estimate of isospin breaking in hadronic vacuum polarization
| Autor: | Hoferichter, Martin, Colangelo, Gilberto, Hoid, Bai-Long, Kubis, Bastian, de Elvira, Jacobo Ruiz, Schuh, Dominic, Stamen, Dominik, Stoffer, Peter |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 131, 161905 (2023) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.131.161905 |
| Popis: | Puzzles in the determination of the hadronic-vacuum-polarization contribution currently impede a conclusive interpretation of the precision measurement of the anomalous magnetic moment of the muon at the Fermilab experiment. One such puzzle concerns tensions between evaluations in lattice QCD and using $e^+e^-\to\text{hadrons}$ cross-section data. In lattice QCD, the dominant isospin-symmetric part and isospin-breaking (IB) corrections are calculated separately, with very different systematic effects. Identifying these two pieces in a data-driven approach provides an opportunity to compare them individually and trace back the source of the discrepancy. Here, we estimate the IB component of the lattice-QCD calculations from phenomenology, based on a comprehensive study of exclusive contributions that can be enhanced via infrared singularities, threshold effects, or hadronic resonances, including, for the first time, in the $e^+e^-\to3\pi$ channel. We observe sizable cancellations among different channels, with a sum that even suggests a slightly larger result for the QED correction than obtained in lattice QCD. We conclude that the tensions between lattice QCD and $e^+e^-$ data therefore cannot be explained by the IB contributions in the lattice-QCD calculations. Comment: 7 pages, 2 figures; journal version |
| Databáze: | arXiv |
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