Strange and charm quark contributions to the muon anomalous magnetic moment in lattice QCD with twisted-mass fermions

We present a lattice calculation of the hadronic vacuum polarization (HVP) contribution of the strange and
charm quarks to the anomalous magnetic moment of the muon in isospin symmetric QCD. We employ the
gauge configurations generated by the Extended Twisted Mass Collaboration (ETMC) with Nf ¼ 2 þ 1 þ 1
flavors of Wilson-clover twisted-mass quarks at five lattice spacings and at values of the quark mass
parameters that are close and/or include the isospin symmetric QCD point of interest. After computing the
small corrections necessary to precisely match this point, and carrying out an extrapolation to the continuum
limit based on the data at lattice spacings a ≃ 0.049, 0.057, 0.068, 0.080 fm and spatial lattice sizes
up to L ≃ 7.6 fm, we obtain aHVP
μ ðsÞ¼ð53.57 0.63Þ × 10−10 and aHVP
μ ðcÞ¼ð14.56 0.13Þ × 10−10, for
the quark-connected strange and charm contributions, respectively. Our findings agree well with the
corresponding results by other lattice groups.