(<i>g</i>− 2)_μand α(<i>M</i>²_<i>Z</i>) re-evaluated using new precise data

Abstract

We update our Standard Model predictions for g-2 of the muon and for the\nhadronic contributions to the running of the QED coupling, Delta\nalpha_had^(5)(M_Z^2). Particular emphasis is put on recent changes in the\nhadronic contributions from new data in the 2pi channel and from the energy\nregion just below 2 GeV. In particular, for the e+e- -&gt; pi+pi- contribution we\ninclude the recent `radiative return' data from KLOE and BaBar. We also include\nthe recent BaBar data on other exclusive channels. We make a detailed study of\nthe effect of replacing the measurements of the inclusive cross section,\nsigma(e+e- -&gt; hadrons), by the sum of the exclusive channels in the energy\ninterval 1.43 &lt; sqrt{s} &lt; 2 GeV, which includes a QCD sum-rule analysis of this\nenergy region. Our favoured prediction for the muon anomalous magnetic moment\nis (g-2)/2 = (11659182.8 +- 4.9)*10^(-10) which is 3.3 sigma below the present\nworld-average measurement. We compare our g-2 value with other recent\ncalculations. Our prediction for the QED coupling, obtained via Delta\nalpha_had^(5)(M_Z^2) = (276.26 +- 1.38)*10^(-4), is alpha(M_Z^2)^(-1) = 128.944\n+- 0.019.\n