QCD determination of the leading order hadronic contribution to the muon g-2

The leading order hadronic contribution to the muon magnetic moment anomaly, $a^{HAD}_\mu$, is determined entirely in the framework of QCD. The result in the light-quark sector, in units of $10^{-10}$, is $a^{HAD}_\mu|_{uds} =686 \pm 26$, and in the heavy-quark sector $a^{HAD}_\mu|_{c} =14.4 \pm 0.1$, and $a^{HAD}_\mu|_{b} =0.29 \pm 0.01$, resulting in $a^{HAD}_\mu = 701 \pm 26$. The main uncertainty is due to the current lattice QCD value of the first and second derivative of the electromagnetic current correlator at the origin. Expected improvement in the precision of these derivatives may render this approach the most accurate and trustworthy determination of the leading order $a^{HAD}_\mu$.Comment: Invited talk at "Les Rencontres de Physique de la Vallee d'Aosta", March 2017. Speaker: C. A. Dominguez. To be published in Nuovo Cimento

Hadronic Corrections at O(alpha^2) to the Energy Spectrum of Muon Decay

We consider the impact of O(alpha^2) hadronic corrections to the energy spectrum of the decay electron in muon decay. We find that the correction can be described, within good approximation, by a linear function in the electron energy. Explicit expressions for the form factors needed in an approach based on dispersion integrals are given.Comment: 12 pages Latex with 4 figure