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The calculation of the hadronic light-by-light scattering contribution to the muon g-2 currently relies entirely on models. Measurements of the form factors which describe the interactions of hadrons with photons can help to constrain the…

High Energy Physics - Phenomenology · Physics 2013-06-26 Andreas Nyffeler

We briefly review the current status of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. Based on various model calculations in the literature, we obtain the estimate a_{mu}^{HLbL} = (102 \pm…

High Energy Physics - Phenomenology · Physics 2017-10-27 Andreas Nyffeler

We present our preliminary results on the calculation of hadronic light-by-light forward scattering amplitudes using vector four-point correlation functions computed on the lattice. Using a dispersive approach, forward scattering amplitudes…

High Energy Physics - Lattice · Physics 2018-04-18 Antoine Gerardin , Jeremy Green , Oleksii Gryniuk , Georg von Hippel , Harvey B. Meyer , Vladimir Pascalutsa , Hartmut Wittig

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

We perform a lattice QCD calculation of the hadronic light-by-light contribution to $(g-2)_\mu$ at the SU(3) flavor-symmetric point $m_\pi=m_K\simeq 420\,$MeV. The representation used is based on coordinate-space perturbation theory, with…

High Energy Physics - Lattice · Physics 2020-10-28 En-Hung Chao , Antoine Gérardin , Jeremy R. Green , Renwick J. Hudspith , Harvey B. Meyer

We summarize our results for hadronic contributions to the anomalous magnetic moment of the muon ($a_\mu$), the one from hadronic vacuum-polarisation (HVP) and the light-by-light scattering contribution (LBL), obtained from the…

High Energy Physics - Phenomenology · Physics 2015-06-03 Tobias Goecke , Christian S. Fischer , Richard Williams

Calculations based on the analytic properties of the required matrix elements allow for a wide range of applications constraining the hadronic contributions to the anomalous magnetic moment of the muon $a_\mu=(g-2)_\mu/2$, both hadronic…

High Energy Physics - Phenomenology · Physics 2024-05-15 Martin Hoferichter

The current measurement of muonic $g - 2$ disagrees with the theoretical calculation by about 3 standard deviations. Hadronic vacuum polarization (HVP) and hadronic light by light (HLbL) are the two types of processes that contribute most…

High Energy Physics - Lattice · Physics 2015-11-18 Luchang Jin , Thomas Blum , Norman Christ , Masashi Hayakawa , Taku Izubuchi , Christoph Lehner

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

In this talk we review the recent progress on the numerical determination of the Hadronic Light-by-Light contribution to the anomalous magnetic moment of the muon and we discuss the role of experimental data on the accuracy of its…

High Energy Physics - Phenomenology · Physics 2017-11-08 P. Masjuan , P. Sanchez-Puertas

The dispersive approach to the hadronic light-by-light contribution to the muon $g-2$ involves an integral over three virtual photon momenta appearing in the light-by-light tensor. Building upon previous works, we systematically derive…

High Energy Physics - Phenomenology · Physics 2025-02-07 Johan Bijnens , Nils Hermansson-Truedsson , Antonio Rodríguez-Sánchez

We present a new strategy for the dispersive evaluation of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon $a_\mu$. The new approach directly applies in the kinematic limit relevant for $a_\mu$: one of…

High Energy Physics - Phenomenology · Physics 2023-04-28 Jan Lüdtke , Massimiliano Procura , Peter Stoffer

We compute the light axial-vector and tensor meson two-photon transition form factors in the soft-wall holographic model of QCD in the flavor-symmetric case. They are used to evaluate the axial-vector and tensor meson contributions to the…

High Energy Physics - Phenomenology · Physics 2024-05-31 Pietro Colangelo , Floriana Giannuzzi , Stefano Nicotri

The short-distance behaviour of the hadronic light-by-light (HLbL) contribution to $(g-2)_{\mu}$ has recently been studied by means of an operator product expansion in a background electromagnetic field. The leading term in this expansion…

High Energy Physics - Phenomenology · Physics 2021-05-12 Johan Bijnens , Nils Hermansson-Truedsson , Laetitia Laub , Antonio Rodríguez-Sánchez

We review the Hadronic Light-by-Light (HLbL) contribution to the muon anomalous magnetic moment. Upcoming measurements will reduce the experimental uncertainty of this precision observable by a factor of four, thus breaking the current…

High Energy Physics - Phenomenology · Physics 2024-04-12 Daniel Melo-Porras , Edilson Alfonso Reyes Rojas , Angelo Raffaele Fazio

Despite recent developments, there are a number of conceptual issues on the hadronic light-by-light (HLbL) contribution to the muon $(g-2)$ which remain unresolved. One of the most controversial ones is the precise way in which…

High Energy Physics - Phenomenology · Physics 2020-12-03 Luigi Cappiello , Oscar Cata , Giancarlo D'Ambrosio , David Greynat , Abhishek Iyer

The hadronic light-by-light scattering contribution to the muon g-2 is the most troublesome component of its theoretical prediction; (1) it cannot be determined from the other measurable quantities, (2) the dimensional argument and the…

High Energy Physics - Lattice · Physics 2007-05-23 Masashi Hayakawa , Thomas Blum , Taku Izubuchi , Norikazu Yamada

We compute the tensor meson pole contributions to the Hadronic Light-by-Light piece of $a_\mu$ in the purely hadronic region, using Resonance Chiral Theory. Given the differences between the dispersive and holographic groups determinations,…

High Energy Physics - Phenomenology · Physics 2026-01-16 Emilio J. Estrada , Pablo Roig

We perform a lattice QCD calculation of the hadronic light-by-light scattering amplitude in a broad kinematical range. At forward kinematics, the results are compared to a phenomenological analysis based on dispersive sum rules for…

High Energy Physics - Lattice · Physics 2015-12-02 Jeremy Green , Oleksii Gryniuk , Georg von Hippel , Harvey B. Meyer , Vladimir Pascalutsa

We compute the hadronic light-by-light scattering contribution to the muon $g-2$ from the up, down, and strange-quark sector directly using lattice QCD. Our calculation features evaluations of all possible Wick-contractions of the relevant…

High Energy Physics - Lattice · Physics 2021-08-18 En-Hung Chao , Renwick J. Hudspith , Antoine Gérardin , Jeremy R. Green , Harvey B. Meyer , Konstantin Ottnad