Massimo Passera

In the first part of the talk I will review the current status of the theoretical prediction of the anomalous magnetic moment of the muon and its comparison with the experimental value. I will then discuss hypothetical errors in the Standard Model prediction that could explain the present discrepancy with the measured value. In particular, an hypothetical increase of the hadroproduction cross section in low-energy e+e- collisions could bridge the muon g-2 discrepancy, but is shown to be unlikely in view of current experimental error estimates. If, nonetheless, this turns out to be the explanation of the discrepancy, then the 95% CL upper bound on the mass of the Higgs boson is reduced to about 130 GeV. In conjunction with the experimental 114.4 GeV 95% CL lower bound, this leaves a narrow window for the mass of this fundamental particle .