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The correction to the muon anomalous magnetic moment from the pion-pole contribution to the hadronic light-by-light scattering is considered using a description of the pi0 - gamma* - gamma* transition form factor based on the large-Nc and…

High Energy Physics - Phenomenology · Physics 2008-11-26 Marc Knecht , Andreas Nyffeler

The $\pi^0$ pole constitutes the lowest-lying singularity of the hadronic light-by-light (HLbL) tensor, and thus provides the leading contribution in a dispersive approach to HLbL scattering in the anomalous magnetic moment of the muon…

High Energy Physics - Phenomenology · Physics 2018-09-14 Martin Hoferichter , Bai-Long Hoid , Bastian Kubis , Stefan Leupold , Sebastian P. Schneider

We summarize our recent new evaluation of the pion-exchange contribution to hadronic light-by-light scattering in the muon g-2. We first derive a new short-distance constraint on the off-shell pion-photon-photon form factor at the external…

High Energy Physics - Phenomenology · Physics 2014-11-20 Andreas Nyffeler

We derive short-distance constraints for the hadronic light-by-light contribution (HLbL) to the anomalous magnetic moment of the muon in the kinematic region where the three virtual momenta are all large. We include the external soft photon…

High Energy Physics - Phenomenology · Physics 2019-10-09 Johan Bijnens , Nils Hermansson-Truedsson , Antonio Rodríguez-Sánchez

We combine existing perturbative results to show that a precise analytic determination of the charm-quark contribution to the hadronic light-by-light (HLbL) part of the muon anomalous magnetic moment is possible. Working in the…

High Energy Physics - Phenomenology · Physics 2026-02-16 Johan Bijnens , Nils Hermansson-Truedsson , Antonio Rodríguez-Sánchez

We report on our preliminary results from the lattice-QCD computation of the hadronic light-by-light (HLbL) contribution to the anomalous magnetic moment of the muon. We use twisted-mass $N_f = 2 + 1 + 1$ gauge ensembles at the physical…

High Energy Physics - Lattice · Physics 2024-12-18 Nikolaos Kalntis , Gurtej Kanwar , Marcus Petschlies , Simone Romiti , Urs Wenger

In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic…

High Energy Physics - Phenomenology · Physics 2017-05-02 Gilberto Colangelo , Martin Hoferichter , Massimiliano Procura , Peter Stoffer

The current $3.7\sigma$ discrepancy between the Standard Model prediction and the experimental value of the muon anomalous magnetic moment could be a hint for the existence of new physics. The hadronic light-by-light contribution is one of…

High Energy Physics - Phenomenology · Physics 2020-11-25 Johan Bijnens , Nils Hermansson-Truedsson , Laetitia Laub , Antonio Rodriguez-Sanchez

I present the main results obtained in a recent work together with Eduardo de Rafael and Arkady Vainshtein on the hadronic light-by-light contribution to muon g-2. We came to the estimate a^{HLbL}_\mu = (10.5 +- 2.6) x 10^{-10}. Here, some…

High Energy Physics - Phenomenology · Physics 2009-07-02 Joaquim Prades

We report preliminary results for the hadronic light-by-light scattering contribution to the muon anomalous magnetic moment. Several ensembles using 2+1 flavors of M\"obius domain-wall fermions, generated by the RBC/UKQCD collaborations,…

High Energy Physics - Lattice · Physics 2019-07-02 Thomas Blum , Norman Christ , Masashi Hayakawa , Taku Izubuchi , Luchang Jin , Chulwoo Jung , Christoph Lehner

The quark-connected part of the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment is computed using lattice QCD with chiral fermions. We report several significant algorithmic improvements and…

High Energy Physics - Lattice · Physics 2016-01-20 Thomas Blum , Norman Christ , Masashi Hayakawa , Taku Izubuchi , Luchang Jin , Christoph Lehner

We develop a method to compute the pion transition form factor directly at arbitrary space-like photon momenta and use it to determine the $\pi^0$-pole contribution to the hadronic light-by-light scattering in the anomalous magnetic moment…

High Energy Physics - Lattice · Physics 2025-07-31 Tian Lin , Mattia Bruno , Xu Feng , Lu-Chang Jin , Christoph Lehner , Chuan Liu , Qi-Yuan Luo

Recently it was pointed out that for the evaluation of the numerically dominant pion-exchange contribution to the hadronic light-by-light scattering correction in the muon g-2, a fully off-shell pion-photon-photon form factor should be…

High Energy Physics - Phenomenology · Physics 2010-04-21 Andreas Nyffeler

The pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon $(g-2)_\mu$ is fully determined by the doubly-virtual pion transition form factor. Although this crucial input quantity is, in…

High Energy Physics - Phenomenology · Physics 2018-10-26 Martin Hoferichter , Bai-Long Hoid , Bastian Kubis , Stefan Leupold , Sebastian P. Schneider

The hadronic corrections to the muon anomalous magnetic moment a_mu, due to the gauge-invariant set of diagrams with dynamical quark loop light-by-light scattering insertions, are calculated in the framework of the nonlocal chiral quark…

High Energy Physics - Phenomenology · Physics 2015-09-30 A. E. Dorokhov , A. E. Radzhabov , A. S. Zhevlakov

We employ a mathematical framework based on rational approximants in order to calculate the pseudoscalar-pole piece of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon, $a_{\mu}^{\textrm{HLbL};P}$. The…

High Energy Physics - Phenomenology · Physics 2017-04-05 Pere Masjuan , Pablo Sanchez-Puertas

We report on our computation of the pion transition form factor ${\cal F}_{P\rightarrow \gamma^*\gamma^*}$ from twisted mass lattice QCD in order to determine the numerically dominant light pseudoscalar pole contribution in the hadronic…

We determine the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon using the framework of Dyson-Schwinger and Bethe-Salpeter equations of QCD. Our result for the pseudoscalar ($\pi^0, \eta, \eta'$)…

High Energy Physics - Phenomenology · Physics 2015-03-17 Tobias Goecke , Christian S. Fischer , Richard Williams

We discuss the use of dispersion relations for the evaluation of the pseudoscalar contributions to the muon anomalous magnetic moment. We point out that, in the absence of experimental data, reconstruction of light-by-light scattering…

High Energy Physics - Phenomenology · Physics 2019-11-15 Kirill Melnikov , Arkady Vainshtein

After a brief introduction on ongoing experimental and theoretical activities on $(g-2)_\mu$, we report on recent progress in approaching the calculation of the hadronic light-by-light contribution with dispersive methods. General…

High Energy Physics - Phenomenology · Physics 2018-04-18 Gilberto Colangelo , Martin Hoferichter , Massimiliano Procura , Peter Stoffer