Hybrid calculation of hadronic vacuum polarization in muon g-2 to 0.48\%

Abstract

We present a new lattice QCD calculation of the leading order hadronic vacuum polarization (LO-HVP) contribution to the muon anomalous magnetic moment $a_{\mu }$. We reduce uncertainties compared to our earlier computation arXiv:2002.12347 by a factor of 1.6. We perform simulations on finer lattices allowing for an even more accurate continuum extrapolation. We also include a small, long-distance contribution obtained using input from experiments in a low-energy regime where they all agree. Combined with other standard model contributions our result, $a_{\mu }^{LO-HVP}=715.1(2.5)(2.3)[3.4]\times 10^{-10}$, leads to a prediction that differs from the recent measurement of $a_{\mu }$ by only 0.5 standard deviations. This provides a remarkable validation of the standard model to 11 digits.

Comments: 85 pages, 54 figures. Changes from v1: changed scale setting from omega mass to pion decay rate; updated the continuum extrapolation functions, the window splitting, the isospin-breaking contributions, and the error estimate for the data-driven tail; added new lattice window results including the long-distance window, comparisons with our 2020 results, and more details on continuum extrapolations