Topical Seminar: Hadronic Contributions to the Light-by-Light piece of muon’s g − 2

by Emilio J. ESTRADA GONZÁLEZ (CINVESTAV)

Thursday 12 Jun 2025, 12:00 → 14:00 Europe/Brussels

The anomalous magnetic moment of the muon (aµ) has been, for two decades, one of the main probes for physics beyond the Standard Model of Elementary Particles.Two weeks ago, the theory initiative published the update of the high precision computation of this observable within the Standard Model, and last week, FNAL announced their results that complete the experimental program. The historic tension between experiment and theory has required us to improve our understanding of the fundamental forces (QED, EW, and QCD) and the methods to compute observables. Precision is the key.

The non-perturbative nature of QCD below 2 GeV has become an urgent issue to be addressed, as it is the main source of error. The hadronic section is split into two contributions: the hadronic vacuum polarization (HVP) and the hadronic light-by-light(HLbL). Our work is focused on the study and improvement of 3 pieces of HLbL: the pseudoscalar poles, the proton-box, and the tensor poles.

The theoretical foundations to account for these contributions and the specific methods for computing the form factors required for each case will be discussed. Finally, an executive summary of the g − 2 theory initiative update, and the current state of the tension will be mentioned.