We present complete results for the hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment $a_\mu$ in the short- and intermediate-distance window regions, which account for roughly 10% and 35% of the total HVP contribution to $a_\mu$, respectively. In particular, we perform lattice-QCD calculations for the isospin-symmetric connected and disconnected contributions, as well as corrections due to strong isospin-breaking. For the short-distance window observables, we investigate the so-called log-enhancement effects as well as the significant oscillations associated with staggered quarks in this region. For the dominant, isospin-symmetric light-quark connected contribution, we obtain $a^{ ll,\,{ \mathrm{ SD}}}_{ \mu}(\mathrm{ conn.}) = 48.139(11)_{ \mathrm{ stat}}(91)_{ \mathrm{ syst}}[92]_{ \mathrm{ total}} \times 10^{ -10}$ and $a^{ ll,\,{ \mathrm{ W}}}_{ \mu}(\mathrm{ conn.}) = 206.90(14)_{ \mathrm{ stat}}(61)_{ \mathrm{ syst}}[63]_{ \mathrm{ total}} \times 10^{ -10}$. We use Bayesian model averaging to fully estimate the covariance matrix between the individual contributions. Our determinations of the complete window contributions are $a^{ { \mathrm{ SD}}}_{ \mu} = 69.05(1)_{ \mathrm{ stat}}(21)_{ \mathrm{ syst}}[21]_{ \mathrm{ total}} \times 10^{ -10}$ and $a^{ { \mathrm{ W}}}_{ \mu} = 236.45(17)_{ \mathrm{ stat}}(83)_{ \mathrm{ syst}}[85]_{ \mathrm{ total}} \times 10^{ -10}$. This work is part of our ongoing effort to compute all contributions to HVP with an overall uncertainty at the few permille level.
Categories: hep-lat hep-ex hep-ph