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 171 MeV pion mass on a $(4.6\mathrm{fm}{)}^3$ spatial volume using the ${32}^3\times 64$ $\mathrm{Iwasaki}+\mathrm{DSDR}$ gauge ensemble of the RBC/UKQCD Collaboration.

• Received 18 November 2015

DOI:https://doi.org/10.1103/PhysRevD.93.014503