Speaker
Description
The uncertainty in the Standard Model (SM) expectation for the anomalous magnetic moment of the muon is currently dominated by that on the hadronic vacuum polarization (HVP) contribution. Discrepancies have been observed between results for this contribution (and related “windowed” quantities) obtained on the lattice and those obtained dispersively, using experimentally measured $e^+ e^-\rightarrow {\it hadrons}$ cross sections as input. The lattice-dispersive discrepancy is of relevance since the lattice-HVP-based version of the SM expectation is compatible with the recent experimental world average, while expectations based on a number of dispersive results lie significantly below that average. I review how the dispersive calculation can be organized to provide results for a number of individual components entering the lattice determinations, and show how these results help to identify the source of the observed lattice-dispersive discrepancies. I also discuss the impact of recent CMD-3 $e^+ e^-\rightarrow \pi^+\pi^-$ cross-section results, which are significantly larger than those obtained by previous experiments in the $\rho$ peak region, on the lattice-dispersive discrepancies observed to date.
