**Antoine Gérardin, CPT, Marseille**

May 5, 2021 at 11:00am

May 5, 2021 at 11:00am

**The theoretical prediction for the muon g-2 : the important role of hadronic contributions**

The Fermilab experiment has just published their new measurement of the anomalous magnetic moment of the muon, confirming the Brookhaven’s measurement with a comparable precision. Combining those two results and using the theory estimate published by the “g-2 theory initiative”, a discrepancy of about 4 sigmas is observed between experiment and the theory prediction based on the Standard Model of particle physics, making the g-2 of the muon a promising observable to identify hints for new physics.

However, the theory error is completely dominated by two, non-perturbative, hadronic contributions : the hadronic vacuum polarization and the hadronic light-by-light scattering contributions. Precise lattice QCD determinations of both quantities are now available and tend to reduce the tension between theory and experiment.

In this talk, I will first present recent progress in calculating both contributions using lattice QCD simulations. Then, I will discuss possible tensions between different theory estimates and the challenges to match the future experimental precision expected in the next few years.