Leading-order hadronic contributions to the lepton anomalous magnetic moments from the lattice

¹ OakLabs GmbH, Neuendorfstr. 20B, D-16761 Hennigsdorf, Germany
² Columbia University, Department of Physics, 538 West 120th Street, 804 Pupin Hall, New York, NY 10027, USA
³ Humboldt-Universität zu Berlin, Institut für Physik, Newtonstr. 15, D-12489 Berlin, Germany
⁴ NIC, DESY, Platanenallee 6, D-15738 Zeuthen, Germany
⁵ Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Strahlen- und Kernphysik, Nußallee 14-16, D-53115 Bonn, Germany
⁶ Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, NM 87545, USA

^a e-mail: marcus.petschlies@hiskp.uni-bonn.de

Published online: 26 April 2016

Abstract

The hadronic leading-order (hlo) contribution to the lepton anomalous magnetic moments a_l^hlo of the Standard Model leptons still accounts for the dominant source of the uncertainty of the Standard Model estimates. We present the results of an investigation of the hadronic leading order anomalous magnetic moments of the electron, muon and tau lepton from first principles in twisted mass lattice QCD. With lattice data for multiple pion masses in the range 230MeV ≲ m_PS ≲ 490 MeV, multiple lattice volumes and three lattice spacings we perform the extrapolation to the continuum and to the physical pion mass and check for all systematic uncertainties in the lattice calculation. As a result we calculate a_l^hlo for the three Standard Model leptons with controlled statistical and systematic error in agreement with phenomenological determinations using dispersion relations and experimental data. In addition, we also give a first estimate of the hadronic leading order anomalous magnetic moments from simulations directly at the physical value of the pion mass.