Hadronic light-by-light scattering contribution to the muon g-2

Abstract

We review recent developments concerning the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. We first discuss why fully off-shell hadronic form factors should be used for the evaluation of this contribution to the g-2. We then reevaluate the numerically dominant pion-exchange contribution in the framework of large-N_C QCD, using an off-shell pion-photon-photon form factor which fulfills all QCD short-distance constraints, in particular, a new short-distance constraint on the off-shell form factor at the external vertex in g-2, which relates the form factor to the quark condensate magnetic susceptibility in QCD. Combined with available evaluations of the other contributions to hadronic light-by-light scattering this leads to the new result a_μ(LbyL; had) = (116 \pm 40) x 10^{-11}, with a conservative error estimate in view of the many still unsolved problems. Some potential ways for further improvements are briefly discussed as well. For the electron we obtain the new estimate a_{e}(LbyL; had) = (3.9 \pm 1.3) x 10^{-14}.

6 pages, 1 figure, to be published in the proceedings of the PhiPsi09 workshop, Oct. 13-16, 2009, Beijing, China

References in corpus (11)

• Measurement of the gamma gamma* --> pi0 transition form factor
• Muon g-2: Review of Theory and Experiment
• Form Factors in the radiative pion decay
• The Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment: Where do we stand?
• Determination of the magnetic susceptibility of the quark condensate using radiative heavy meson decays
• Chiral magnetization of non-Abelian vacuum: a lattice study
• Pseudo scalar contributions to light-by-light correction of muon g-2 in AdS/QCD
• Pion pole light-by-light contribution to g-2 of the muon in a nonlocal chiral quark model
• A Fresh Look into the Neutron EDM and Magnetic Susceptibility
• 1/N_c corrections to the magnetic susceptibility of the QCD vacuum
• Zero mode solutions of quark Dirac equations in QCD as the sources of chirality violating condensates

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• The hadronic light by light contribution to the $(g-2{)}_{\mu }$ with holographic models of QCD
• Hadronic Light-by-Light and the Pion Polarizability
• Reconciling $(g-2{)}_{\mu }$ and charged lepton flavour violating processes through a doubly charged scalar
• A fresh look at hadronic light-by-light scattering in the muon g-2 with the Dyson-Schwinger approach
• The Muon Anomalous Magnetic Moment and the Pion Polarizability
• The muon g-2 discrepancy: new physics or a relatively light Higgs?
• New physics for muon anomalous magnetic moment and its electroweak precision analysis
• Hadronic contribution to the muon g-2 from a Dyson-Schwinger perspective