Lattice Calculation of Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment

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 demonstrate their effectiveness through specific calculations which show a reduction in statistical errors by more than an order of magnitude. The most realistic of these calculations is performed with a near-physical, 139 MeV pion mass on a (5.5 fm)³ spatial volume using the 48³ × 96 Iwasaki gauge ensemble of the RBC/UKQCD Collaboration.