Z ) re-evaluated using new precise data

Abstract

We update our Standard Model predictions for g 2 of the muon and for the hadronic contributions to the running of the QED coupling, �� (5) (M 2 Z ). Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2� channel and from the energy region just below 2 GeV. In particular, for the e + e − ! � + � − contribution we include the recent ‘radiative return’ data from KLOE and BaBar. We also include the recent BaBar data on other exclusive channels. We make a detailed study of the effect of replacing the measurements of the inclusive cross section, �(e + e − ! hadrons), by the sum of the exclusive channels in the energy interval 1.43 < p s < 2 GeV, which includes a QCD sum-rule analysis of this energy region. Our favoured prediction for the muon anomalous magnetic moment is (g 2)/2 = (11659182.8±4.9)·10 −10 which is 3.3� below the present world-average measurement. We compare our g 2 value with other recent calculations. Our prediction for the QED coupling, obtained via �� (5) (M 2