The anomalous magnetic moment of the muon is providing a persistent hint for new physics, in the form of an intriguing 3 - 4σ tension between Standard Model (SM) theory and experiment. We expect the Fermilab Muon g-2 experiment (E989) to soon release first results towards the target of a fourfold improvement over the Brookhaven E821 determination. In the near future, we also look forward to measurements from the methodologically independent experimental program at J-PARC (E34). To leverage the new experimental efforts, the theory errors must be reduced to the same level as the experimental uncertainties. The dominant sources of uncertainty in the SM prediction of the muon g-2 are from the hadronic corrections, in particular, from the hadronic vacuum polarization (HVP) and hadronic light-by-light scattering contributions. There are a number of complementary theoretical efforts underway to better understand and quantify these hadronic corrections, including dispersive methods, lattice QCD, and effective field theories, as well as a number of different experimental efforts to provide inputs to dispersive, data-driven evaluations. A concerted effort of the theory community to improve upon and scrutinize the existing SM results has been made possible thanks to the formation of the Muon g-2 Theory Initiative and a Whitepaper summarizing the current theory status has been recently finalized.
Matching the precision of the new experiments requires to determine the HVP contribution at the per-mille level. The goal of this workshop is to bring together theorists from the lattice QCD community to discuss, assess, and compare the status of the various efforts, and to map out strategies for obtaining the best theoretical predictions and for reaching a sub-percent precision.
The workshop extends the series of topical workshops by the Muon g-2 Theory Initiative, featuring a mix of talks and dedicated discussion sessions on specific topics.