Improved Evaluation of the Hadronic Vacuum Polarization Contributions to Muon $g-2$ and $\barα_{\rm QED}(M_Z)$ Using High Order QCD Calculations
Abstract
Description
We use recently evaluated radiative and nonperturbative corrections to production of heavy quarks by a vector current to give very precise theoretical calculations of the high energy ($t^{1/2}\geq \sqrt{2}$ GeV) imaginary part of the photon vacuum polarization function, ${\rm Im}Π(t)$. This allows us to improve the corresponding contributions to the muon (or any other lepton) $g-2$ anomaly and to the running QED constant on the $Z$, $\barα_{\rm QED}(M_Z)$. This decreases the error in the evaluations by a factor between two and six for the high energy contribution, and by some 50\% for the overall result. We find for the hadronic contributions $a_h=6993.4\pm110.0\times10^{-11}$ and $Δα_h=272.59\pm4.09\times10^{-4}\,.$
12 pages, uses RevTeX, 1 postscript figure appended
12 pages, uses RevTeX, 1 postscript figure appended