High-precision lattice QCD calculations of the muon anomalous magnetic moment

In 2021, the most precise measurement of the muon’s anomalous magnetic moment and a new high-precision lattice quantum chromodynamics calculation have in turn kindled, then dimmed, hopes for seeing signs of new physics. State of the art calculations, made possible by a series of recent advances, will be key to understanding these conflicting results. In 2021, the most precise measurement of the muon’s anomalous magnetic moment and a new high-precision lattice quantum chromodynamics calculation have in turn kindled, then dimmed, hopes for seeing signs of new physics. State-of-the-art calculations, made possible by a series of recent advances, will be key to understanding these conflicting results. Key advances In 2021, the most precise measurement of the muon’s anomalous magnetic moment was reported, showing a remarkable 4.2σ tension with the generally accepted theoretical value. Reported at the same time, a new high-precision lattice quantum chromodynamics calculation is at odds with the theoretical value, reducing the tension with experiment to 1.6σ, yet increasing tensions with other theoretical calculations to 3.7σ. The key to understanding these conflicting results lies in the value for the hadronic vacuum polarization. Advances in lattice quantum chromodynamics calculations will provide a new way to derive this quantity with high precision.