2026-06-01T17:58:30Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/1025852024-05-31T14:45:07Zcom_20.500.14352_14col_20.500.14352_15

Phenomenological estimate of isospin breaking in hadronic vacuum polarization Hoferichter, Martin Colangelo, Gilberto Hoid, Bai-Long Kubis, Bastian Ruiz De Elvira Carrascal, Jacobo Schuh, Dominic Stamen, Dominik Stoffer, Pete 539.1 Anomalous magnetic moment Short distance constraints Quark mass dependence By light contribution Vector meson masses Pi-pi scattering Pair production Muon G-2 Equation E(+)E(-) Partículas 2207 Física Atómica y Nuclear 2023 Descuento SCOAP 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- -> 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- -> 3 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. Swiss National Science Foundation German Research Foundation (DFG) Ministerio de Economia y Competitividad (España) Depto. de Física Teórica Fac. de Ciencias Físicas Instituto de Física de Partículas y del Cosmos (IPARCOS) TRUE pub Descuento UCM 2024-04-02T18:31:21Z 2024-04-02T18:31:21Z 2023-10-18 journal article VoR https://hdl.handle.net/20.500.14352/102585 0031-9007 10.1103/PhysRevLett.131.161905 1079-7114 eng 200020_175791 PCEFP2_181117 PCEFP2_194272 196253076-TRR 110 RYC2019-027605-I Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ open access application/pdf American Physical Society