Pith. sign in

REVIEW 3 major objections 5 minor 6 cited by

Complete dispersive evaluation of the hadronic light-by-light contribution to muon $g-2$

T0 review · 3 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash

Pith's one-line read A complete dispersive evaluation determines the hadronic light-by-light contribution to the muon's magnetic moment as $a_\mu^\text{HLbL} = 101.9(7.9)\times 10^{-11}$.

desk verdict First complete dispersive HLbL evaluation with a realistic error budget; the U(3) axial-vector assumption is the main thing to probe, but it is handled as a transparent systematic. read the letter →

arxiv 2412.00190 v2 pith:AOYSNPLJ submitted 2024-11-29 hep-ph hep-exhep-latnucl-th

classification hep-phhep-exhep-latnucl-th
keywords muong-2hadroniclight-by-lightdispersiveapproachtransitionformfactorsshort-distanceconstraintsoperatorproductexpansionaxial-vectormesons
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper presents the first complete dispersive evaluation of the hadronic light-by-light (HLbL) contribution to the muon's anomalous magnetic moment. The central result is $a_\mu^\text{HLbL} = 101.9(7.9)\times 10^{-11}$, which improves on the previous data-driven estimate by more than a factor of two and reaches the precision required for the final result of the muon g-2 experiment. The evaluation reconstructs the HLbL tensor from its discontinuities, expressing it in terms of hadronic matrix elements measured in experiment, and matches the low-energy hadronic description to short-distance constraints from perturbative QCD and the operator product expansion. The piece of the calculation that remains most assumption-dependent is the axial-vector meson contribution, fixed through U(3) symmetry with a 30% assigned uncertainty.

What carries the argument

The central mechanism is a Bardeen–Tung–Tarrach decomposition of the four-photon HLbL tensor, which reduces the amplitude to 54 scalar coefficient functions (12 independent after the equations of motion). The master formula for $a_\mu$ integrates these functions against known kernels over the three photon virtualities. The functions are reconstructed dispersively from their discontinuities, which are saturated by a finite set of hadronic intermediate states: pseudoscalar poles ($\pi^0,\eta,\eta'$) with transition form factors from data, two-meson boxes and rescattering, and narrow-resonance approximations for axial-vector, scalar, and tensor mesons. In the deep-Euclidean region the same functions are matched to the perturbative quark loop with $\alpha_s$ corrections, and in the asymmetric region to the operator product expansion controlled by the vector-vector-axial-vector correlator $w_{L,T}$. A newly introduced effective-pole parametrization estimates the error from intermediate states that lie between the hadronic and asymptotic descriptions.

What would settle it

New data on the $f_1$ or $f_1'$ transition form factor that deviate from the U(3)-symmetric parameterization by more than the assigned 30% would move the axial-vector contribution beyond the quoted systematic error.

Watch

Extended reading notes

Core claim

The authors establish a data-driven, dispersive value for the hadronic light-by-light contribution to the muon's $g-2$, $a_\mu^\text{HLbL} = 101.9(7.9)\times 10^{-11}$, by reconstructing the HLbL tensor from its unitarity cuts and matching the sum of exclusive hadronic states to short-distance constraints. This is the first such evaluation that includes axial-vector resonances ($a_1$, $f_1$, $f_1'$), scalar and tensor resonances, the full vector-vector-axial-vector correlator for the OPE region, and a dedicated estimate of the matching uncertainty via an effective-pole ansatz. The result agrees with the 2020 phenomenological consensus, $92(19)\times 10^{-11}$, but reduces the uncertainty by more than half, meeting the precision target set for the final result of the muon g-2 experiment.

Load-bearing premise

The calculation assumes that the axial-vector meson transition form factors follow U(3) symmetry with no more than 30% deviation; if the true symmetry breaking is larger, the central value shifts outside the quoted uncertainty.

Editorial extensions

If this is right

  • The uncertainty of the HLbL contribution drops from $19\times 10^{-11}$ to $7.9\times 10^{-11}$, so the hadronic light-by-light piece no longer dominates the theory error for the muon $g-2$ prediction.
  • The quoted precision meets the requirement set by the final result of the muon g-2 experiment, making the comparison between the Standard-Model prediction and experiment sensitive mainly to the hadronic vacuum polarization contribution.
  • The new value agrees with the 2020 phenomenological estimate but with an uncertainty reduced by more than a factor of two, strengthening the data-driven benchmark against which lattice QCD calculations are compared.
  • The axial-vector resonance contribution is now the largest subleading term with an assumption-based error, so new measurements of the $f_1$ and $f_1'$ transition form factors directly test the main systematic uncertainty.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A natural next step would be a direct dispersive calculation of the $a_1$ transition form factor from $\tau$-decay data, which could replace the U(3)-symmetry assumption with an experimental determination.
  • If the effective-pole matching error is as small as quoted, then the dominant remaining model dependence in the subleading contributions sits in the tensor-meson treatment; a triangle-kinematics dispersive calculation of the $f_2$ contribution would provide a sharp cross-check.
  • The small tension with two of the lattice QCD evaluations, if it persists, may point to a systematic effect in one of the methods; the present result offers a data-driven reference point for locating the difference.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper presents a data-driven dispersive evaluation of the hadronic light-by-light (HLbL) contribution to the muon anomalous magnetic moment. The HLbL tensor is reconstructed from its discontinuities using four-point dispersion relations, with contributions from pseudoscalar poles, meson boxes, rescattering, axial-vector and tensor resonances, heavy scalars, and a matching to pQCD and OPE short-distance constraints. The final result is a_mu^HLbL = 101.9(7.9) x 10^-11 (Eq. (8)), which the authors state meets the precision requirements of the final Fermilab result. The paper relies on a companion paper (Ref. [82]) for many technical details.

Significance. If correct, this would be the most precise data-driven determination of a_mu^HLbL to date, reducing the uncertainty of the 2020 White Paper evaluation by more than a factor of two and providing a sharp benchmark for comparisons with lattice QCD. The paper is notable for its detailed error budget, separating experimental, matching, systematic, and effective-pole uncertainties, and for demonstrating stability of the integral under variation of the matching scale Q0 and the OPE parameter r (Fig. 5). The result is also falsifiable in the sense that future BESIII and Belle II measurements of axial-vector transition form factors, as well as improved lattice calculations, will directly test the assumptions that underlie the axial-vector and tensor contributions.

major comments (3)
  1. [Exclusive hadronic states / Table II / Eq. (7)] The axial-vector sector is the most load-bearing input for the claimed precision, yet the a1(1260) transition form factors are not extracted from direct data. The Letter fixes the f1 and f1' TFF normalizations and mixing angle from e+e- data and then defines the complete set of axial-vector TFFs using U(3) symmetry, assigning a global 30% uncertainty 'to account for possible symmetry violations.' This 30% is not derived from a spread of models, fits, or dispersion relations; the supporting comparison with the dispersive VVA calculation of Ref. [81] constrains only the singly-virtual a1 form factor, not the doubly-virtual TFFs that dominate the HLbL integral. Since the axial-vector contribution is 12.2(2.3) x 10^-11 (Table II), the largest non-pseudoscalar subleading piece, a U(3) violation of 40-50% in the a1 TFF normalizations or virtuality dependence would shift the result by more than the quoted 7.9 x 10^-11 total uncertainty and would invalidate the precision claim of Eq. (8). Please calibrate the 30% by explicit sensitivity studies (e.g., 50% variations or an alternative model spread) or soften the claim accordingly.
  2. [Matching to short-distance constraints / Fig. 4 / Table II] The effective-pole model (P(2200), A(1700)) is introduced to estimate the impact of missing higher intermediate states in the matching between hadronic and pQCD/OPE regions. The Letter assigns an effective-pole uncertainty larger than the entire effective-pole contribution (3.9 x 10^-11 vs. contributions of 2.0 and 1.2 x 10^-11 in Table II), which is conservative in that specific sense. However, the effective-pole amplitude is an ad-hoc construct with masses fixed at 2.2 GeV and 1.7 GeV and a TFF scale varied only over the same range as Q0; no explicit functional form is given in the Letter. A different pole structure or asymptotic behavior could shift the central value beyond the quoted eff uncertainty. Please provide the explicit effective-pole parameterization in the Letter or in a form that can be checked against Ref. [82], and demonstrate robustness to the assumed pole masses and the number of poles.
  3. [Tensor contributions / Table II / Eq. (7)] The tensor contribution is estimated using a quark-model-inspired TFF with a single nonvanishing form factor, with the scale set to M_rho. The Letter adds a 100% uncertainty on the total tensor contribution 'to protect against the cancellation observed between a_mu[Pi1,2] and a_mu[Pi3-12],' but this protects against the sign cancellation rather than against individual normalization or shape errors. The two tensor components in Table II are -2.6(3) and -5.1(7) x 10^-11; a 50% error in the f2(1270) TFF alone would shift the sum by roughly 3.9 x 10^-11, exceeding the quoted total sys error. Please provide a more robust estimate of the tensor uncertainty, for example by varying the TFF scale and form independently or by including a dispersive D-wave treatment as the paper itself identifies as future work.
minor comments (5)
  1. [Title and abstract] The phrase 'complete dispersive evaluation' overstates the treatment of axial-vector and tensor states, which are evaluated in narrow-resonance and quark-model approximations rather than fully dispersively; consider qualifying the claim as 'complete within the stated hadronic approximations' or moving the stronger claim to the conclusions.
  2. [Figure 4 caption] The caption refers to the effective pole P(2200) without defining its amplitude; please either define it in the text or refer explicitly to the equation in Ref. [82] where it is introduced.
  3. [Table II] The 'Eff.' rows list central values without uncertainties, while Eq. (7) quotes an effective-pole uncertainty; please clarify whether the quoted eff uncertainty is meant to cover these entries or is an additional assignment.
  4. [Exclusive hadronic states] The sentence 'all contributions but a single TFF vanish' is ambiguous; please specify which of the tensor TFFs is kept and in which basis the vanishing occurs.
  5. [Table I] The K± box entry is quoted as -0.5(0); please provide the actual uncertainty (even if negligible) to avoid the appearance of an exactly vanishing error.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: the final result is a sum of externally fitted inputs and explicitly estimated matching contributions, not a redefinition of its own input.

full rationale

The derivation chain is self-contained. Equation (8) is obtained by adding the dispersive pseudoscalar/box/rescattering contributions from Table I, the subleading hadronic and short-distance-matched contributions from Table II, and the independent charm-loop estimate. None of these inputs use a_mu^HLbL as a fit target or as a defining condition. The axial-vector TFFs are parameterized from fits to f1/f1' data in Refs. [73,74] and extended to a1 via an explicitly stated U(3) symmetry assumption with a 30% systematic uncertainty; this is a modeling input, not a quantity derived from the final result. The VVA correlator input [81] is a separate dispersive calculation used for the OPE region and as a cross-check, and the effective-pole and tensor contributions are estimates with uncertainties assigned at or above their full size. No equation in the paper defines the output in terms of its own fitted values, and no load-bearing conclusion is justified solely by a self-citation chain. The reliance on prior work by the same authors is reliance on data-driven analyses whose inputs are external experiments and dispersion relations, which does not constitute circularity.

Assumptions & free parameters 6 free parameters · 7 assumptions · 2 invented entities

The central result depends on a number of scales and models introduced or inherited from fits. The effective poles are ad hoc constructs with no independent evidence; the matching and TFF scales are varied or assigned uncertainties. The axial-vector TFF parameters are constrained by external data, so they are not ad hoc, but they carry fit uncertainties.

free parameters (6)
  • Matching scale Q0 = 1.5 GeV (central), varied 1.2-2.0 GeV
    Splits the integration into hadronic (Qi<Q0) and pQCD/OPE (Qi>Q0) regions; the final result's stability under its variation is used to estimate the matching uncertainty.
  • OPE matching parameter r = 1/4 (central), varied 1/8-1/2
    Defines the mixed region where one virtuality is smaller than the other two; scanned to estimate the matching uncertainty.
  • Effective pole masses M_P^eff, M_A^eff = 2.2 GeV and 1.7 GeV
    Mass parameters for the fictitious poles introduced to model the intermediate-energy asymptotic matching, determined from the symmetric asymptotic limit rather than from data.
  • Effective pole TFF scale = varied with Q0 in [1.2,2.0] GeV
    Scale parameter of the effective-pole transition form factors, one of the dominant systematic uncertainties.
  • Tensor TFF scale = M_rho = 0.775 GeV
    Quark-model-inspired scale for the f2/a2/f2' form factors, assumed equal to the rho mass based on f0(980)/a0(980) studies.
  • Axial-vector TFF normalizations and f1-f1' mixing angle
    Input from global fits to e+e- and radiative decay data in Refs [73,74]; not fitted in this paper, but the central result depends on them.
assumptions (7)
  • domain assumption The HLbL tensor can be reconstructed from its discontinuities via dispersion relations in four-point kinematics, and the infinite sum of intermediate states can be truncated to the listed exclusive hadronic states plus pQCD/OPE matching.
    Invoked in 'Dispersive formalism' and 'Exclusive hadronic states'; if higher multi-meson states contribute significantly beyond the effective-pole estimate, the central value shifts.
  • domain assumption The narrow-resonance approximation is valid for the axial-vector states a1, f1, f1' and heavy scalars/tensors.
    Explicitly verified only for f0(980) and a0(980) in Refs [107,108]; assumed for the other resonances by mass suppression.
  • domain assumption U(3) symmetry determines the full set of axial-vector TFFs from the f1 data.
    Section 'Exclusive hadronic states'; the paper adds a global 30% uncertainty for symmetry violations, indicating the assumption is not exact.
  • ad hoc to paper The quark-model-inspired TFF with a single nonzero form and scale M_rho describes the tensor and heavy-scalar contributions.
    Section 'Exclusive hadronic states'; this is a simplified set-up, with a 100% uncertainty added on the total tensor contribution.
  • ad hoc to paper The effective-pole model with parameters fixed in the symmetric asymptotic limit captures the intermediate-energy matching between hadronic and pQCD/OPE regions.
    Section 'Matching to short-distance constraints'; the assigned uncertainty is larger than the entire effective-pole contribution.
  • domain assumption The OPE limit relates the HLbL tensor to the VVA correlator, and the cancellation found in Ref [80] holds beyond leading order.
    Section 'Matching to short-distance constraints'; relies on independent Bijnens et al. analysis.
  • standard math Standard QCD factorization and alpha_s evolution from Refs [124,125] apply in the pQCD quark-loop region.
    Section 'Matching to short-distance constraints'.
invented entities (2)
  • Effective pole P(2200)
    purpose: Models the asymptotic matching for the II1,2 scalar functions in the mixed region, representing missing higher intermediate states.
    Not a physical resonance; mass 2.2 GeV chosen to reproduce the asymptotic coefficient. No independent observable.
  • Effective pole A(1700)
    purpose: Models the asymptotic matching for II3-12 scalar functions.
    Not a physical resonance; mass 1.7 GeV chosen for matching. No independent observable.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Complete dispersive evaluation of the hadronic light-by-light contribution to muon $g-2$." pith.science (2026). https://pith.science/paper/AOYSNPLJ

@misc{pith2026241200190,
  author       = {Pith},
  title        = {Pith review of: Complete dispersive evaluation of the hadronic light-by-light contribution to muon $g-2$},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/AOYSNPLJ}},
  note         = {Machine review of arXiv:2412.00190}
}
abstract

Hadronic light-by-light (HLbL) scattering defines one of the critical contributions in the Standard-Model prediction of the anomalous magnetic moment of the muon. In this Letter, we present a complete evaluation using a dispersive formalism, in which the HLbL tensor is reconstructed from its discontinuities, expressed in terms of simpler hadronic matrix elements that can be extracted from experiment. Profiting from recent developments in the determination of axial-vector transition form factors, short-distance constraints for the HLbL tensor, and the vector-vector-axial-vector correlator, we obtain $a_\mu^\text{HLbL}=101.9(7.9)\times 10^{-11}$, which meets the precision requirements set by the final result of the Fermilab experiment.

Figures

Figures reproduced from arXiv: 2412.00190 by the authors.

Figure 1
Figure 1. FIG. 1: HVP (left) and HLbL (right) contributions to [PITH_FULL_IMAGE:figures/full_fig_p001_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2: Unitarity diagrams in a dispersive approach to HLbL [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3: Diagrams relevant for SDCs: ( [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figures from the paper (3 more)
Figure 4
Figure 4. Figure 4: FIG. 4: Matching between the sum of hadronic states, [PITH_FULL_IMAGE:figures/full_fig_p003_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5: Stability of the [PITH_FULL_IMAGE:figures/full_fig_p004_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6: Comparison of our result for [PITH_FULL_IMAGE:figures/full_fig_p005_6.png]

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 6 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Tensor meson transition form factors in holographic QCD and the muon $g-2$

    hep-ph 2025-01 conditional novelty 7.0 of 10

    Holographic QCD predicts a positive tensor-meson contribution of about +11e-11 to the muon g-2, driven by a previously omitted doubly-virtual form factor.

  2. Longitudinal short-distance constraints on hadronic light-by-light scattering and tensor meson contributions to the muon $g-2$

    hep-ph 2025-01 conditional novelty 6.0 of 10

    In hard-wall holographic QCD, the infinite tower of tensor mesons fills most of the missing symmetric longitudinal short-distance constraint and yields a total hadronic light-by-light contribution of about +11 x 10^-1...

  3. Dispersive analysis of the pion vector form factor without zeros

    hep-ph 2025-01 conditional novelty 6.0 of 10

    Imposing the absence of complex zeros in the pion vector form factor reduces the dominant systematic uncertainty and makes the tensions between CMD-3 and other e+e- data sets appear sharper, including in the pion char...

  4. Hadronic vacuum polarization for the muon $g-2$ from lattice QCD: Long-distance and full light-quark connected contribution

    hep-lat 2024-12 conditional novelty 6.0 of 10

    The light-quark connected hadronic vacuum polarization contribution to muon g-2 is determined to 0.69% precision, 655.2(4.5) x 10^-10, from lattice QCD.

  5. Dispersion relation for hadronic light-by-light scattering: $\eta$ and $\eta'$ poles

    hep-ph 2024-12 conditional novelty 6.0 of 10

    A dispersive analysis of the eta and eta' transition form factors yields data-driven pole contributions to the muon g-2 of 14.7(9) x 10^-11 and 13.5(7) x 10^-11.

  6. Dispersion relation for hadronic light-by-light scattering: subleading contributions

    hep-ph 2024-11 conditional novelty 6.0 of 10

    A dispersive evaluation gives a_mu^HLbL subleading = 33.2(7.2) x 10^-11 and total = 101.9(7.9) x 10^-11.

Reference graph

Works this paper leans on

138 extracted references · 3 canonical work pages · cited by 6 Pith papers

  1. [82]

    Hoferichter, P

    M. Hoferichter, P. Stoffer, and M. Zillinger (2024), 2412.00178

  2. [81]

    Bijnens, N

    J. Bijnens, N. Hermansson-Truedsson, and A. Rodr ´ ıguez-S´ anchez, JHEP 02, 167 (2023), 2211.17183

  3. [1]

    J. S. Schwinger, Phys. Rev. 73, 416 (1948)

  4. [2]

    Kusch and H

    P. Kusch and H. M. Foley, Phys. Rev. 74, 250 (1948)

  5. [3]

    exp”) errors already shown in Table II, we include the following uncertainty esti- mates: (ii) matching (“match

    derive from the orig- inal 54 Π i and represent the dynamical content of the theory. In this Letter, we follow the original approach from Refs. [21, 71] and consider dispersion relations in four-point kinematics, i.e., for the Mandelstam variables of the scattering process (3) with fixed photon virtual- ities, in contrast to an alternative approach in tri...

  6. [4]

    D. P. Aguillard et al. (Muon g − 2), Phys. Rev. D 110, 032009 (2024), 2402.15410

  7. [5]

    D. P. Aguillard et al. (Muon g − 2), Phys. Rev. Lett. 131, 161802 (2023), 2308.06230

  8. [6]

    Aoyama et al., Phys

    T. Aoyama et al., Phys. Rept. 887, 1 (2020), 2006.04822

Show all 138 references
  1. [7]

    Grange et al

    J. Grange et al. (Muon g − 2) (2015), 1501.06858

  2. [8]

    Aoyama, T

    T. Aoyama, T. Kinoshita, and M. Nio, Atoms 7, 28 (2019)

  3. [9]

    Aoyama, M

    T. Aoyama, M. Hayakawa, T. Kinoshita, and M. Nio, Phys. Rev. Lett. 109, 111808 (2012), 1205.5370

  4. [10]

    Gnendiger, D

    C. Gnendiger, D. St¨ ockinger, and H. St¨ ockinger-Kim, Phys. Rev. D 88, 053005 (2013), 1306.5546

  5. [11]

    Czarnecki, W

    A. Czarnecki, W. J. Marciano, and A. Vainshtein, Phys. Rev. D 67, 073006 (2003), [Erratum: Phys. Rev. D 73, 119901 (2006)], hep-ph/0212229

  6. [12]

    Keshavarzi, D

    A. Keshavarzi, D. Nomura, and T. Teubner, Phys. Rev. D 97, 114025 (2018), 1802.02995

  7. [13]

    Davier, A

    M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, Eur. Phys. J. C 77, 827 (2017), 1706.09436

  8. [14]

    Hoferichter, B.-L

    M. Hoferichter, B.-L. Hoid, and B. Kubis, JHEP 08, 137 (2019), 1907.01556

  9. [15]

    Colangelo, M

    G. Colangelo, M. Hoferichter, and P. Stoffer, JHEP 02, 006 (2019), 1810.00007

  10. [16]

    Keshavarzi, D

    A. Keshavarzi, D. Nomura, and T. Teubner, Phys. Rev. D 101, 014029 (2020), 1911.00367

  11. [17]

    Davier, A

    M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, Eur. Phys. J. C 80, 241 (2020), [Erratum: Eur. Phys. J. C 80, 410 (2020)], 1908.00921

  12. [18]

    Melnikov and A

    K. Melnikov and A. Vainshtein, Phys. Rev. D 70, 113006 (2004), hep-ph/0312226

  13. [19]

    B.-L. Hoid, M. Hoferichter, and B. Kubis, Eur. Phys. J. C 80, 988 (2020), 2007.12696

  14. [20]

    Colangelo, M

    G. Colangelo, M. Hoferichter, M. Procura, and P. Stof- fer, Phys. Rev. Lett. 118, 232001 (2017), 1701.06554

  15. [21]

    Masjuan and P

    P. Masjuan and P. S´ anchez-Puertas, Phys. Rev. D 95, 054026 (2017), 1701.05829

  16. [22]

    Hoferichter, B.-L

    M. Hoferichter, B.-L. Hoid, B. Kubis, S. Leupold, and S. P. Schneider, Phys. Rev. Lett. 121, 112002 (2018), 1805.01471

  17. [23]

    Colangelo, M

    G. Colangelo, M. Hoferichter, M. Procura, and P. Stof- fer, JHEP 04, 161 (2017), 1702.07347

  18. [24]

    G´ erardin, H

    A. G´ erardin, H. B. Meyer, and A. Nyffeler, Phys. Rev. D 100, 034520 (2019), 1903.09471

  19. [25]

    Hoferichter, B.-L

    M. Hoferichter, B.-L. Hoid, B. Kubis, S. Leupold, and S. P. Schneider, JHEP 10, 141 (2018), 1808.04823

  20. [26]

    Colangelo, F

    G. Colangelo, F. Hagelstein, M. Hoferichter, L. Laub, and P. Stoffer, Phys. Rev. D 101, 051501 (2020), 1910.11881

  21. [27]

    Bijnens, N

    J. Bijnens, N. Hermansson-Truedsson, and A. Rodr ´ ıguez-S´ anchez, Phys. Lett. B 798, 134994 (2019), 1908.03331

  22. [28]

    Pauk and M

    V. Pauk and M. Vanderhaeghen, Eur. Phys. J. C 74, 3008 (2014), 1401.0832

  23. [29]

    Colangelo, F

    G. Colangelo, F. Hagelstein, M. Hoferichter, L. Laub, and P. Stoffer, JHEP 03, 101 (2020), 1910.13432

  24. [30]

    Jegerlehner, The Anomalous Magnetic Moment of the Muon, vol

    F. Jegerlehner, The Anomalous Magnetic Moment of the Muon, vol. 274 (Springer, Cham, 2017)

  25. [31]

    Danilkin and M

    I. Danilkin and M. Vanderhaeghen, Phys. Rev. D 95, 014019 (2017), 1611.04646

  26. [32]

    Eichmann, C

    G. Eichmann, C. S. Fischer, and R. Williams, Phys. Rev. D 101, 054015 (2020), 1910.06795

  27. [33]

    Knecht, S

    M. Knecht, S. Narison, A. Rabemananjara, and D. Ra- betiarivony, Phys. Lett. B 787, 111 (2018), 1808.03848

  28. [34]

    Calmet, S

    J. Calmet, S. Narison, M. Perrottet, and E. de Rafael, Phys. Lett. B 61, 283 (1976). 6

  29. [35]

    Roig and P

    P. Roig and P. S´ anchez-Puertas, Phys. Rev. D 101, 074019 (2020), 1910.02881

  30. [36]

    Colangelo, M

    G. Colangelo, M. Hoferichter, A. Nyffeler, M. Passera, and P. Stoffer, Phys. Lett. B 735, 90 (2014), 1403.7512

  31. [37]

    A. Kurz, T. Liu, P. Marquard, and M. Steinhauser, Phys. Lett. B 734, 144 (2014), 1403.6400

  32. [38]

    Crivellin, M

    A. Crivellin, M. Hoferichter, C. A. Manzari, and M. Montull, Phys. Rev. Lett. 125, 091801 (2020), 2003.04886

  33. [39]

    Hoferichter and T

    M. Hoferichter and T. Teubner, Phys. Rev. Lett. 128, 112002 (2022), 2112.06929

  34. [40]

    Malaescu and M

    B. Malaescu and M. Schott, Eur. Phys. J. C 81, 46 (2021), 2008.08107

  35. [41]

    Keshavarzi, W

    A. Keshavarzi, W. J. Marciano, M. Passera, and A. Sir- lin, Phys. Rev. D 102, 033002 (2020), 2006.12666

  36. [42]

    Stamen, D

    D. Stamen, D. Hariharan, M. Hoferichter, B. Kubis, and P. Stoffer, Eur. Phys. J. C 82, 432 (2022), 2202.11106

  37. [43]

    Colangelo, M

    G. Colangelo, M. Hoferichter, and P. Stoffer, Phys. Lett. B 814, 136073 (2021), 2010.07943

  38. [44]

    Colangelo, M

    G. Colangelo, M. Hoferichter, B. Kubis, and P. Stoffer, JHEP 10, 032 (2022), 2208.08993

  39. [45]

    Colangelo, A

    G. Colangelo, A. X. El-Khadra, M. Hoferichter, A. Ke- shavarzi, C. Lehner, P. Stoffer, and T. Teubner, Phys. Lett. B 833, 137313 (2022), 2205.12963

  40. [46]

    Hoferichter, B.-L

    M. Hoferichter, B.-L. Hoid, B. Kubis, and D. Schuh, JHEP 08, 208 (2023), 2307.02546

  41. [47]

    Hoferichter, G

    M. Hoferichter, G. Colangelo, B.-L. Hoid, B. Kubis, J. Ruiz de Elvira, D. Schuh, D. Stamen, and P. Stof- fer, Phys. Rev. Lett. 131, 161905 (2023), 2307.02532

  42. [48]

    Davier, A

    M. Davier, A. Hoecker, A.-M. Lutz, B. Malaescu, and Z. Zhang, Eur. Phys. J. C 84, 721 (2024), 2312.02053

  43. [49]

    Stoffer, G

    P. Stoffer, G. Colangelo, and M. Hoferichter, JINST 18, C10021 (2023), 2308.04217

  44. [50]

    F. V. Ignatov et al. (CMD-3), Phys. Rev. Lett. 132, 231903 (2024), 2309.12910

  45. [51]

    F. V. Ignatov et al. (CMD-3), Phys. Rev. D 109, 112002 (2024), 2302.08834

  46. [52]

    Bors´ anyi et al

    S. Bors´ anyi et al. (BMWc), Nature 593, 51 (2021), 2002.12347

  47. [53]

    T. P. Leplumey and P. Stoffer (2025), 2501.09643

  48. [54]

    Alexandrou et al

    C. Alexandrou et al. (ETM), Phys. Rev. D 107, 074506 (2023), 2206.15084

  49. [55]

    C` e et al., Phys

    M. C` e et al., Phys. Rev. D 106, 114502 (2022), 2206.06582

  50. [56]

    Blum et al

    T. Blum et al. (RBC, UKQCD), Phys. Rev. D 108, 054507 (2023), 2301.08696

  51. [57]

    Bazavov et al

    A. Bazavov et al. (Fermilab Lattice, HPQCD, MILC), Phys. Rev. D 107, 114514 (2023), 2301.08274

  52. [58]

    Blum et al

    T. Blum et al. (RBC, UKQCD) (2024), 2410.20590

  53. [59]

    Boccaletti et al

    A. Boccaletti et al. (BMWc) (2024), 2407.10913

  54. [60]

    Bazavov et al

    A. Bazavov et al. (Fermilab Lattice, HPQCD, MILC) (2024), 2412.18491

  55. [61]

    Djukanovic, G

    D. Djukanovic, G. von Hippel, S. Kuberski, H. B. Meyer, N. Miller, K. Ottnad, J. Parrino, A. Risch, and H. Wit- tig (2024), 2411.07969

  56. [62]

    Campanario, H

    F. Campanario, H. Czy˙ z, J. Gluza, T. Jeli´ nski, G. Ro- drigo, S. Tracz, and D. Zhuridov, Phys. Rev. D 100, 076004 (2019), 1903.10197

  57. [63]

    Colangelo et al

    G. Colangelo et al. (2022), 2203.15810

  58. [64]

    Colangelo, M

    G. Colangelo, M. Hoferichter, J. Monnard, and J. Ruiz de Elvira, JHEP 08, 295 (2022), [Erratum: JHEP 09, 177 (2024)], 2207.03495

  59. [65]

    Ignatov and R

    F. Ignatov and R. N. Lee, Phys. Lett. B 833, 137283 (2022), 2204.12235

  60. [66]

    Abbiendi et al

    G. Abbiendi et al. (2022), 2201.12102

  61. [67]

    Monnard, Ph.D

    J. Monnard, Ph.D. thesis, Universit¨ at Bern (2021), URL https://boristheses.unibe.ch/2825/

  62. [68]

    Aliberti et al

    R. Aliberti et al. (2024), 2410.22882

  63. [69]

    J. P. Lees et al. (BaBar), Phys. Rev. D 108, L111103 (2023), 2308.05233

  64. [70]

    Colangelo, M

    G. Colangelo, M. Hoferichter, B. Kubis, M. Procura, and P. Stoffer, Phys. Lett. B 738, 6 (2014), 1408.2517

  65. [71]

    Colangelo, M

    G. Colangelo, M. Hoferichter, M. Procura, and P. Stof- fer, JHEP 09, 091 (2014), 1402.7081

  66. [72]

    Hoferichter, G

    M. Hoferichter, G. Colangelo, M. Procura, and P. Stof- fer, Int. J. Mod. Phys. Conf. Ser. 35, 1460400 (2014), 1309.6877

  67. [73]

    Colangelo, M

    G. Colangelo, M. Hoferichter, M. Procura, and P. Stof- fer, JHEP 09, 074 (2015), 1506.01386

  68. [74]

    Hoferichter, B

    M. Hoferichter, B. Kubis, and M. Zanke, JHEP 08, 209 (2023), 2307.14413

  69. [75]

    Zanke, M

    M. Zanke, M. Hoferichter, and B. Kubis, JHEP 07, 106 (2021), 2103.09829

  70. [76]

    Hoferichter, P

    M. Hoferichter, P. Stoffer, and M. Zillinger, JHEP 04, 092 (2024), 2402.14060

  71. [77]

    Hoferichter and P

    M. Hoferichter and P. Stoffer, JHEP 05, 159 (2020), 2004.06127

  72. [78]

    Bijnens, N

    J. Bijnens, N. Hermansson-Truedsson, L. Laub, and A. Rodr ´ ıguez-S´ anchez, JHEP 04, 240 (2021), 2101.09169

  73. [79]

    Bijnens, N

    J. Bijnens, N. Hermansson-Truedsson, L. Laub, and A. Rodr ´ ıguez-S´ anchez, JHEP 10, 203 (2020), 2008.13487

  74. [80]

    Bijnens, N

    J. Bijnens, N. Hermansson-Truedsson, and A. Rodr ´ ıguez-S´ anchez (2024), 2411.09578

  75. [83]

    L¨ udtke, M

    J. L¨ udtke, M. Procura, and P. Stoffer (2024), 2410.11946

  76. [84]

    Tarrach, Nuovo Cim

    R. Tarrach, Nuovo Cim. A 28, 409 (1975)

  77. [85]

    W. A. Bardeen and W. K. Tung, Phys. Rev. 173, 1423 (1968), [Erratum: Phys. Rev. D 4, 3229 (1971)]

  78. [86]

    L¨ udtke, M

    J. L¨ udtke, M. Procura, and P. Stoffer, JHEP 04, 125 (2023), 2302.12264

  79. [87]

    Eichmann, C

    G. Eichmann, C. S. Fischer, and W. Heupel, Phys. Rev. D 92, 056006 (2015), 1505.06336

  80. [88]

    Hoferichter, B

    M. Hoferichter, B. Kubis, and D. Sakkas, Phys. Rev. D 86, 116009 (2012), 1210.6793

  81. [89]

    S. P. Schneider, B. Kubis, and F. Niecknig, Phys. Rev. D 86, 054013 (2012), 1206.3098

  82. [90]

    Hoferichter, B.-L

    M. Hoferichter, B.-L. Hoid, B. Kubis, and J. L¨ udtke, Phys. Rev. Lett. 128, 172004 (2022), 2105.04563

  83. [91]

    Hoferichter, B

    M. Hoferichter, B. Kubis, S. Leupold, F. Niecknig, and S. P. Schneider, Eur. Phys. J. C 74, 3180 (2014), 1410.4691

  84. [92]

    Hanhart, A

    C. Hanhart, A. Kup´ s´ c, U.-G. Meißner, F. Stollenwerk, and A. Wirzba, Eur. Phys. J. C 73, 2668 (2013), [Erra- tum: Eur. Phys. J. C 75, 242 (2015)], 1307.5654

  85. [93]

    Stollenwerk, C

    F. Stollenwerk, C. Hanhart, A. Kup´ s´ c, U.-G. Meißner, and A. Wirzba, Phys. Lett. B 707, 184 (2012), 1108.2419

  86. [94]

    S. Holz, J. Plenter, C.-W. Xiao, T. Dato, C. Hanhart, B. Kubis, U.-G. Meißner, and A. Wirzba, Eur. Phys. J. C 81, 1002 (2021), 1509.02194

  87. [95]

    Kubis and J

    B. Kubis and J. Plenter, Eur. Phys. J. C 75, 283 (2015), 1504.02588

  88. [96]

    Holz, Ph.D

    S. Holz, Ph.D. thesis, University of Bonn (2022), URL https://nbn-resolving.org/urn:nbn:de:hbz: 5-67976

  89. [97]

    S. Holz, C. Hanhart, M. Hoferichter, and B. Kubis, Eur. 7 Phys. J. C 82, 434 (2022), [Addendum: Eur. Phys. J. C 82, 1159 (2022)], 2202.05846

  90. [98]

    S. Holz, M. Hoferichter, B.-L. Hoid, and B. Kubis (2024), 2412.16281

  91. [99]

    S. Holz, M. Hoferichter, B.-L. Hoid, and B. Kubis (2024), 2411.08098

  92. [100]

    Hoferichter, D

    M. Hoferichter, D. R. Phillips, and C. Schat, Eur. Phys. J. C 71, 1743 (2011), 1106.4147

  93. [101]

    Garc ´ ıa-Mart ´ ın and B

    R. Garc ´ ıa-Mart ´ ın and B. Moussallam, Eur. Phys. J. C 70, 155 (2010), 1006.5373

  94. [102]

    Danilkin and M

    I. Danilkin and M. Vanderhaeghen, Phys. Lett. B 789, 366 (2019), 1810.03669

  95. [103]

    Moussallam, Eur

    B. Moussallam, Eur. Phys. J. C 73, 2539 (2013), 1305.3143

  96. [104]

    Danilkin, O

    I. Danilkin, O. Deineka, and M. Vanderhaeghen, Phys. Rev. D 101, 054008 (2020), 1909.04158

  97. [105]

    Hoferichter and P

    M. Hoferichter and P. Stoffer, JHEP 07, 073 (2019), 1905.13198

  98. [106]

    Sch¨ afer, M

    H. Sch¨ afer, M. Zanke, Y. Korte, and B. Kubis, Phys. Rev. D 108, 074025 (2023), 2307.10357

  99. [107]

    Lu and B

    J. Lu and B. Moussallam, Eur. Phys. J. C 80, 436 (2020), 2002.04441

  100. [108]

    Danilkin, M

    I. Danilkin, M. Hoferichter, and P. Stoffer, Phys. Lett. B 820, 136502 (2021), 2105.01666

  101. [109]

    Deineka, I

    O. Deineka, I. Danilkin, and M. Vanderhaeghen (2024), 2410.12894

  102. [110]

    Achard et al

    P. Achard et al. (L3), JHEP 03, 018 (2007)

  103. [111]

    Achard et al

    P. Achard et al. (L3), Phys. Lett. B 526, 269 (2002), hep-ex/0110073

  104. [112]

    J. P. Lees et al. (BaBar), Phys. Rev. D 107, 072001 (2023), 2207.10340

  105. [113]

    Aubert et al

    B. Aubert et al. (BaBar), Phys. Rev. D 76, 092005 (2007), [Erratum: Phys. Rev. D 77, 119902 (2008)], 0708.2461

  106. [114]

    Leutgeb, J

    J. Leutgeb, J. Mager, and A. Rebhan, Phys. Rev. D 107, 054021 (2023), 2211.16562

  107. [115]

    Navas et al

    S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

  108. [116]

    G. A. Schuler, F. A. Berends, and R. van Gulik, Nucl. Phys. B 523, 423 (1998), hep-ph/9710462

  109. [117]

    Leutgeb, J

    J. Leutgeb, J. Mager, and A. Rebhan (2024), 2411.10432

  110. [118]

    Cappiello, O

    L. Cappiello, O. Cat` a, G. D’Ambrosio, D. Greynat, and A. Iyer, Phys. Rev. D 102, 016009 (2020), 1912.02779

  111. [119]

    Leutgeb and A

    J. Leutgeb and A. Rebhan, Phys. Rev. D 101, 114015 (2020), 1912.01596

  112. [120]

    Masjuan, P

    P. Masjuan, P. Roig, and P. S´ anchez-Puertas, J. Phys. G 49, 015002 (2022), 2005.11761

  113. [121]

    Knecht, JHEP 08, 056 (2020), 2005.09929

    M. Knecht, JHEP 08, 056 (2020), 2005.09929

  114. [122]

    Colangelo, F

    G. Colangelo, F. Hagelstein, M. Hoferichter, L. Laub, and P. Stoffer, Eur. Phys. J. C 81, 702 (2021), 2106.13222

  115. [123]

    L¨ udtke and M

    J. L¨ udtke and M. Procura, Eur. Phys. J. C 80, 1108 (2020), 2006.00007

  116. [124]

    Herren and M

    F. Herren and M. Steinhauser, Comput. Phys. Com- mun. 224, 333 (2018), 1703.03751

  117. [125]

    Eichmann, C

    G. Eichmann, C. S. Fischer, T. Haeuser, and O. Regen- felder (2024), 2411.05652

  118. [126]

    Vainshtein, Phys

    A. Vainshtein, Phys. Lett. B 569, 187 (2003), hep- ph/0212231

  119. [127]

    K. G. Chetyrkin, J. H. K¨ uhn, and M. Steinhauser, Com- put. Phys. Commun. 133, 43 (2000), hep-ph/0004189

  120. [128]

    T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, C. Jung, and C. Lehner (RBC, UKQCD), Phys. Rev. Lett. 124, 132002 (2020), 1911.08123

  121. [129]

    Knecht, S

    M. Knecht, S. Peris, M. Perrottet, and E. de Rafael, JHEP 03, 035 (2004), hep-ph/0311100

  122. [130]

    E.-H. Chao, R. J. Hudspith, A. G´ erardin, J. R. Green, and H. B. Meyer, Eur. Phys. J. C 82, 664 (2022), 2204.08844

  123. [131]

    E.-H. Chao, R. J. Hudspith, A. G´ erardin, J. R. Green, H. B. Meyer, and K. Ottnad, Eur. Phys. J. C 81, 651 (2021), 2104.02632

  124. [132]

    Fodor, A

    Z. Fodor, A. G´ erardin, L. Lellouch, K. K. Szab´ o, B. C. Toth, and C. Zimmermann (BMWc) (2024), 2411.11719

  125. [133]

    T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, C. Jung, C. Lehner, and C. Tu (RBC, UKQCD), Phys. Rev. D 111, 014501 (2025), 2304.04423

  126. [134]

    C. F. Redmer, Nuovo Cim. C 47, 247 (2024)

  127. [135]

    Prades, E

    J. Prades, E. de Rafael, and A. Vainshtein, Adv. Ser. Direct. High Energy Phys. 20, 303 (2009), 0901.0306

  128. [136]

    Altmannshofer et al

    W. Altmannshofer et al. (Belle-II), PTEP 2019, 123C01 (2019), [Erratum: PTEP 2020, 029201 (2020)], 1808.10567

  129. [137]

    Ablikim et al

    M. Ablikim et al. (BESIII), Chin. Phys. C 44, 040001 (2020), 1912.05983

  130. [2020]

    Glasgow consensus

    and the “Glasgow consensus” [133] (PdR V 2009), as well as the lattice-QCD calculations by RBC/UKQCD [128, 131] (including the charm loop from Ref. [130]), Mainz [129, 130], and BMWc [132]. vinced that Eq. (8) represents a realistic and conservative estimate of the current unc...

Pith tools

Reviewed August 12, 2026 · model on record in the stance chip above.