| Hadronic Contributions to (2007) | |||||||||||||
Abstract | |||||||||||||
| . The new experiment planned at Brookhaven to measure the anomalous magnetic moment of the muon a¯ j (g ¯ \Gamma 2)=2 will improve the present accuracy of 7 ppm by about a factor of 20. This requires a careful reconsideration of the theoretical uncertainties of the g \Gamma 2 predictions, which are dominated by the error of the contribution from the light quarks to the photon vacuum polarization. This issue is crucial also for the precise determination of the running fine structure constant at the Z--peak as LEP/SLC experiments continue to increase their precision. In this paper we present an updated analysis of the hadronic vacuum polarization using all presently available e + e \Gamma data. This seems to be justified because previous work on the subject was based to some extent on preliminary or incomplete experimental data. Contributions from different energy ranges are presented separately for g \Gamma 2 of the muon and the ø --lepton and for ff(M 2 Z ). We obtain the resu... | |||||||||||||
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