{
  "abstract": "The dominant contribution to the hadronic vaccum polarization (HVP) of the muon $g-2$ can be calculated using the hadronic spectrum in $τ^- \\to π^-π^0ν_τ$ decay, provided isospin breaking (IB) corrections are properly accounted for. Among these corrections, IB in the $ρππ$ coupling has been pointed out as a missing ingredient. In this work, we calculate this IB effect within the impulse approximation using a symmetry-preserving framework based on Dyson-Schwinger and Bethe-Salpeter equations, incorporating fully dressed quark propagators and meson Bethe-Salpeter amplitudes. We then estimate its effect in the HVP contribution to the muon $g-2$. As a natural extension, we also compute the IB in the ratio of $ϕK^+K^-/ϕK^0\\bar{K^0}$ couplings and compare with existing data. We obtain a coupling ratio $g_{ρ^0π^+π^-}/g_{ρ^+π^+π^0} = 1.0024(17)(1)$, which yields an isospin-breaking correction of $Δa_μ^{\\mathrm{HVP,LO}}[ρππ] = -2.32(1.64)\\times 10^{-10}$ to the two-pion contribution to the muon anomalous magnetic moment extracted from $τ$ decay data.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.28506",
  "author_total": 3,
  "authors": [
    {
      "name": "A. Bashir"
    },
    {
      "name": "G. López-Castro"
    },
    {
      "name": "K. Raya"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9nwgzbb24erv8.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.28506",
  "fulltext_url": null,
  "id": "9nwgzbb24erv8",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.28506",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "nucl-th"
    ],
    [
      "openalex",
      "3106|Quantum Chromodynamics and Particle Interactions"
    ]
  ],
  "openalex": "W7223105048",
  "pdf_url": "https://arxiv.org/pdf/2610.28506",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9nwgzbb24erv8.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:04Z",
      "native_id": "2610.28506",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.28506"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-th",
      "subfield": "nuclear"
    }
  ],
  "title": "Isospin breaking in $ρππ$ couplings: $ρ^{+,0}$ width difference and muon $g-2$",
  "title_text": "Isospin breaking in ρππ couplings: ρ^+,0 width difference and muon g−2",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:04Z",
  "url": "https://research.draconitic.com/paper/9nwgzbb24erv8",
  "venue": "arXiv",
  "versions": []
}