English

Revisiting the Muon Anomaly from $e^+ e^-\to$ Hadrons

High Energy Physics - Phenomenology 2025-10-21 v5 High Energy Physics - Experiment High Energy Physics - Lattice

Abstract

In this talk, I revisit and present a more comprehensive estimate of the lowest order Hadronic Vacuum Polarization (HVP) contribution aμhvploa_\mu\vert_{hvp}^{lo} to the muon anomalous magnetic moment (muon anomaly) from e+ee^+e^-\to Hadrons obtained recently in Ref.[1]. New CMD-3 data on e+e2πe^+e^-\to 2\pi [2] and precise BABAR [3] and recent BELLE2 [4] e+e3πe^+e^-\to 3\pi data are usedto update the estimate of the I=0I=0 isoscalar channel below the ϕ\phi-meson mass. Adding the data compiled by PDG22 [5] above 1 GeV and the QCD improved continuum used in Ref. [1], one deduces: aμlohvp=(7043±37)×1011a_\mu\vert^{hvp}_{lo}=(7043\pm 37)\times 10^{-11} .A comparison with previous data driven (e+ee^+e^- and τ\tau-decays) estimates is done.Including the Higher Order aμhvphoa_\mu\vert_{hvp}^{ho} corrections, the phenomenological estimate of the Hadronic Light by Light scattering up to NLO and the QED and Electroweak (EW) contributions, one obtains: Δaμphenoaμexpaμpheno=(81±41)×1011\Delta a_\mu^{pheno}\equiv a_\mu^{exp}-a_{\mu}^{pheno}= (81\pm 41)\times 10^{-11} where the recent experimental value aμexpa_\mu^{exp} [6] has been used. This result consolidates the previous one in Ref.[1], after adding the π0γ,ηγ\pi^0\gamma,\eta\gamma contributions, and can be compared with the one from the most precise Lattice result Δaμlattice=(90±56)×1011\Delta a_\mu^{lattice}= (90\pm 56)\times 10^{-11}. Then, we deduce the (tentative) SM prediction average : ΔaμSM=(87±33)×1011\Delta a_\mu^{SM} = (87\pm 33)\times 10^{-11}. We complete the paper by revising our predictions on the LO HVP contributions in adding the π0γ,ηγ\pi^0\gamma,\eta\gamma contributions to the ones in Ref.[1]. Then, we obtain: aτlohvp=(3516±25)×1011a_\tau\vert^{hvp}_{lo}=(3516\pm 25)\times 10^{-11} and Δαhad(5)(MZ2)=(2770.7±4.5)×105\Delta \alpha^{(5)}_{had}(M_Z^2)=(2770.7\pm 4.5)\times 10^{-5} for 5 flavours.

Keywords

Cite

@article{arxiv.2507.18239,
  title  = {Revisiting the Muon Anomaly from $e^+ e^-\to$ Hadrons},
  author = {Stephan Narison},
  journal= {arXiv preprint arXiv:2507.18239},
  year   = {2025}
}

Comments

Latex source files, 22 pages, 17 figures, 2 Tables. Comparison with estimates from tau-decays added. Some misprints corrected. Review Talk given at QCD25, 40th anniversary, 30 june - 4 july 2025 (Montpellier-FR) Version to appear in the Journal of SubParticle and Cosmology (Elsevier) Proceedings

R2 v1 2026-07-01T04:16:42.043Z