Résumé:

summarize our self-contained determinations of the lowest order hadronic contributions to the anomalous magnetic moments a_{\mu,\tau} of the muon and tau leptons, the running QED coupling \alpha(M_Z) and the muonium hyperfine splitting \nu. Using as a revised estimate of the light-by light scattering: a_\mu(LL)=85(18) 10^{-11}, we deduce: a_\mu^{SM} = 116 591 861(78) 10^{-11}, a_\tau^{SM} = 117 759(7) 10^{-8}, giving: a_\mu^{SM}-a_\mu^{exp}=162(170) 10^{-11}. We also obtain: \alpha^{-1}(M_Z)=128.926(25) and the Fermi energy splitting: \nu_F^{SM}=4 459 031 783(229) {Hz}. Lower bounds on some eventual new physics are given, while \nu_F^{SM} leads e.g. to m_\mu/m_e=206.768 276(11) in remarkable agreement with the data.

Commentaires: Talk presented at the 1st High-Energy Physics Madagascar International Conference Series (HEP-MAD'01) 27th sept-5th oct. 2001, Antananarivo