Hadronic Vacuum Polarization: (g−2)μ versus Global Electroweak Fits

Andreas Crivellin, Martin Hoferichter, Claudio Andrea Manzari, Marc Montull
Hadronic vacuum polarization (HVP) is not only a critical part of the standard model (SM) prediction for the anomalous magnetic moment of the muon (g−2), but also a crucial ingredient for global fits to electroweak (EW) precision observables due to its contribution to the running of the finestructure constant encoded in Δ(5)had. We find that with modern EW precision data, including the measurement of the Higgs mass, the global fit alone provides a competitive, independent determination of
more » ... d|EW=270.2(3.0)×10−4. This value actually lies below the range derived from e+e−→hadrons cross section data, and thus goes into the opposite direction as would be required if a change in HVP were to bring the SM prediction for (g−2) into agreement with the Brookhaven measurement. Depending on the energy where the bulk of the changes in the cross section occurs, reconciling experiment and SM predictions for (g−2) by adjusting HVP would thus not necessarily weaken the case for physics beyond the SM (BSM), but to some extent shift it from (g−2) to the EW fit. We briefly explore some options of BSM scenarios that could conceivably explain the ensuing tension
doi:10.5167/uzh-191488 fatcat:lqnyniastvdqrcqufblirkqe6m