Compatibility between $e^+e^-$ and $\tau$ decay data in the di-pion channel and implications for $a_\mu^\mathrm{SM}$ and CVC tests

Abstract

We have revisited the isospin-breaking corrections relating $\sigma(e^+e^-\to\pi^+\pi^-)$ and $\Gamma(\tau^-\to\pi^-\pi^0\nu_\tau)$. We confirm that the associated uncertainty is under control, so that tau data can also be used to predict accurately the leading hadronic contribution to the muon anomalous magnetic moment and precision conserved vector current tests can be carried out.