Speaker
Description
We revisit the isospin-breaking corrections relating the e+e- hadronic cross section and the tau decay spectral function, focusing on the dipion channel, that gives the dominant contribution to the hadronic vacuum polarization piece of the muon g-2. We test different types of electromagnetic and weak form factors and show that both, the Gounaris-Sakurai and a dispersive-based approach, describe accurately τ lepton and e+e- data (less when KLOE measurements are included in the fits) and comply reasonably well with analyticity constraints. From these results we obtain the isospin-breaking contribution to the conserved vector current (CVC) prediction of the BR(τ→ππντ) and to the 2π hadronic vacuum polarization (HVP) contribution to the muon g-2, in agreement with previous determinations and with similar precision. Our results abound in the utility of using tau data-based results in the updated data-driven prediction of the muon g-2 in the Standard Model.
