Speaker
Description
The first new experimental results on the anomalous magnetic moment of the muon from Fermilab, published in April 2021, confirm the tension with the Standard Model prediction, now at $4.2\sigma$. The uncertainty in the theory prediction is by far dominated by hadronic effects. I discuss how different important contributions can be made more precise by using rigorous theoretical constraints, especially due to analyticity: this includes hadronic vacuum polarisation due to $3\pi$ and $\pi^0\gamma$ intermediate states, and hadronic light-by-light scattering via the largest individual contribution therein, the $\pi^0$-pole term. The latter is determined in terms of the $\pi^0$ transition form factor, for which a representation that incorporates all low-lying singularities and matches correctly onto the asymptotic behaviour expected from perturbative QCD has been derived. Further, ongoing, extensions of this work will briefly be mentioned.
