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.
Categories: hep-lat hep-ph