Electromagnetic isospin breaking in hadronic vacuum polarization within a VMD model
Abstract
One of the challenging components of modern lattice-QCD computations of the leading hadronic vacuum polarization contribution to the muon (g−2)μ is the isospin-breaking correction due to electromagnetism. Dominated by long distances, this correction suffers from severe signal-to-noise issues and finite-volume effects. To provide infinite-volume benchmarks for various quark-level Wick contractions, we estimate their sizes phenomenologically at the physical point, using a previously developed vector-meson-dominance model. The pion contributions in this model sum to around −7.1× 10−10, dominated by the electromagnetic pion mass shift. The ultraviolet-finite (2+2)a ("dumbbell") contraction accounts for approximately two thirds of this model sum; for both, about 30% comes from Euclidean times beyond 2.8 fm.
Related
- The hadronic-vacuum-polarization contribution to the muon anomalous magnetic moment in isospin-symmetric lattice QCD with twisted-mass fermions
- Spacelike and timelike kernels for the hadronic vacuum polarization contribution to the muon lifetime
- Hadronic vacuum polarization and light-by-light scattering in representative infrared-improved soft-wall holographic QCD models
- Diffusion and shear viscosity coefficients of hot isospin asymmetric strange hadronic matter using a chiral SU(3) model
- Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed 0+→ 0+ beta decays
BibTeX
@misc{biloshytskyi2026electromagnetic,
title = {{Electromagnetic isospin breaking in hadronic vacuum polarization within a VMD model}},
author = {Volodymyr Biloshytskyi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.11861},
eprint = {2610.11861},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.11861},
}
RIS
TY - UNPB
TI - Electromagnetic isospin breaking in hadronic vacuum polarization within a VMD model
AU - Volodymyr Biloshytskyi
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.11861
UR - https://arxiv.org/abs/2610.11861
AB - One of the challenging components of modern lattice-QCD computations of the leading hadronic vacuum polarization contribution to the muon (g−2)_μ is the isospin-breaking correction due to electromagnetism. Dominated by long distances, this correction suffers from severe signal-to-noise issues and finite-volume effects. To provide infinite-volume benchmarks for various quark-level Wick contractions, we estimate their sizes phenomenologically at the physical point, using a previously developed vector-meson-dominance model. The pion contributions in this model sum to around −7.1× 10^−10, dominated by the electromagnetic pion mass shift. The ultraviolet-finite (2+2)a ("dumbbell") contraction accounts for approximately two thirds of this model sum; for both, about 30% comes from Euclidean times beyond 2.8 fm.
ER -