Tests of hadronic vacuum polarization fits for the muon anomalous magnetic moment

Abstract

We construct a physically motivated model for the isospin-one non-strange vacuum polarization function Pi(Q^2) based on a spectral function given by vector-channel OPAL data from hadronic tau decays for energies below the tau mass and a successful parametrization, employing perturbation theory and a model for quark-hadron duality violations, for higher energies. Using a covariance matrix and Q^2 values from a recent lattice simulation, we then generate fake data for Pi(Q^2) and use it to test fitting methods currently employed on the lattice for extracting the hadronic vacuum polarization contribution to the muon anomalous magnetic moment. This comparison reveals a systematic error much larger than the few-percent total error sometimes claimed for such extractions in the literature. In particular, we find that errors deduced from fits using a Vector Meson Dominance ansatz are misleading, typically turning out to be much smaller than the actual discrepancy between the fit and exact model results. The use of a sequence of Padé approximants, recently advocated in the literature, appears to provide a safer fitting strategy.

7 pages, 4 figures. Presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany

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Cited by in corpus (18)

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• Finite-volume effects in the muon anomalous magnetic moment on the lattice
• A New Strategy for the Lattice Evaluation of the Leading Order Hadronic Contribution to $(g-2{)}_{\mu }$
• The hadronic vacuum polarization with twisted boundary conditions
• Lattice calculation of the leading strange quark-connected contribution to the muon $g-2$
• Hadronic vacuum polarization function within dispersive approach to QCD
• Chiral extrapolation of the leading hadronic contribution to the muon anomalous magnetic moment
• A ChPT estimate of the strong-isospin-breaking contribution to the anomalous magnetic moment of the muon
• Leading-order hadronic contributions to the electron and tau anomalous magnetic moments
• Lattice QCD Studies of the Leading Order Hadronic Contribution to the Muon $g-2$
• Hadronic contributions to electroweak observables within DPT
• Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice
• Finite-volume effects in the hadronic vacuum polarization
• Vector correlator and scale determination in lattice QCD
• Explaining muon $g-2$ anomaly in a non-universal $U(1{)}_X$ extended SUSY theory
• Towards the physical point hadronic vacuum polarisation from Moebius DWF
• Neutrino mass and charged lepton flavor violation in an extended left-right symmetric model