Hadronic Contribution to the muon $g-2$ factor

Abstract

The lowest order hadronic contribution to the $g-2$ factor of the muon is analyzed in the framework of the operator product expansion at short distances, and a QCD finite energy sum rule designed to quench the role of the $e^{+}{e}^{-}$ data. This procedure reduces the discrepancy between experiment and theory, $\Delta a_{\mu }\equiv a_{\mu }^{EXP}-a_{\mu }^{SM}$, from $\Delta a_{\mu }=28.7(8.0)\times 10^{-10}$ to $\Delta a_{\mu }=19.2(8.0)\times 10^{-10}$, i.e. without changing the uncertainty.

Comments: Revised version with additional paragraphs