Tea in the Atrium Room: 307

Colloquium Room: 307 Title: The Muon Magnetic Moment with Lattice QCD Abstract: The magnetic moment of muon can be characterized by its gyro-magnetic factor $g$, which is numerically close to 2. Fermilab announced a new experimental result for muon $g-2$ on June 3, 2025. The new result is consistent with the previous BNL measurement, but with about 4 times higher precision. For the Standard Model prediction, the recent theoretical muon $g-2$ white paper was released on May 27, 2025. The new theory result is consistent with the new experimental result, but is about 3 sigma larger than the previous theory white paper result, released on June 8, 2020. Two hadronic contributions, HVP (hadronic vacuum polarization) and HLbL (hadronic light-by-light), are the dominant sources of the theoretical uncertainty. The change in the central value is largely due to the many advances in lattice QCD calculations of these hadronic contributions, particularly the HVP contribution. In this talk, I will describe the theoretical determination of muon $g-2$ with focus on the lattice QCD calculations of the hadronic contributions.