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Burkhardt, H.; Pietrzyk, B.
Physics letters. B, 1995, Letnik: 356, Številka: 2Journal Article
We have updated the evaluation of the hadronic contribution to the running of the QED fine structure constant. It is obtained from a dispersion integral over a parametrization of the measured cross section of e +e − → hadrons. We find this contribution to be 0.0280 ± 0.0007 at s = M Z 2 corresponding to α −1( M Z 2) = 128.89 ± 0.09. We have also parametrized the corrections to α as a function of energy and discuss the influence on the luminosity measurements at LEP.
