Header

UZH-Logo

Maintenance Infos

Phenomenological Estimate of Isospin Breaking in Hadronic Vacuum Polarization


Hoferichter, Martin; Colangelo, Gilberto; Hoid, Bai-Long; Kubis, Bastian; Ruiz de Elvira, Jacobo; Schuh, Dominic; Stamen, Dominik; Stoffer, Peter (2023). Phenomenological Estimate of Isospin Breaking in Hadronic Vacuum Polarization. Physical Review Letters, 131(16):161905.

Abstract

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−→3π 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.

Abstract

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−→3π 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.

Statistics

Citations

Dimensions.ai Metrics

Altmetrics

Downloads

1 download since deposited on 29 Dec 2023
1 download since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Scopus Subject Areas:Physical Sciences > General Physics and Astronomy
Uncontrolled Keywords:General Physics and Astronomy, Particle Physics
Language:English
Date:18 October 2023
Deposited On:29 Dec 2023 10:44
Last Modified:28 Jun 2024 03:31
Publisher:American Physical Society
ISSN:0031-9007
OA Status:Hybrid
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1103/physrevlett.131.161905
PubMed ID:37925732
Project Information:
  • : FunderDeutsche Forschungsgemeinschaft
  • : Grant ID
  • : Project Title
  • : FunderMinisterio de Economía y Competitividad
  • : Grant ID
  • : Project Title
  • Content: Published Version
  • Language: English
  • Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)