Hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon at the physical pion mass

Abstract

We present a lattice QCD calculation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon using $N_f=2+1+1$ flavors of staggered quarks with masses tuned to their physical values. Our final result, in the continuum limit, reads $a_{\mu }^{\mathrm{hlbl}}=125.5(11.6{)}_{\mathrm{stat}}(0.4{)}_{\mathrm{syst}}\times 10^{-11}$ where the first error is statistical and the second is systematic. Light, strange and charm-quark contributions are considered. In addition to the connected and leading disconnected contributions, we also include an estimate of the sub-leading disconnected diagrams. Our result is compatible with previous lattice QCD and data-driven dispersive determinations.

Comments: 28 pages, 18 figures