In this presentation Gfitter results from the global Standard Model (SM) fit to electroweak precision data are discussed. We have used the latest measurements of m_top and M_W and the most recent results for direct Higgs searches at LEP and Tevatron.
We obtain M_H=121^{+17}_{-6} GeV and a 95% CL upper limit of 155 GeV for the SM Higgs mass. The forth-order result for the strong coupling constant is given by alpha_S(M_Z^2)=0.1193 +- 0.0028(exp) +- 0.0001(theo). In addition the electroweak fit has been performed with the top mass determined from the ttbar cross-section as measured at Tevatron.
In the global fit of the Standard Model using Gfitter, electroweak precision observables as well as constraints from direct Higgs searches have been compared with state-of-the-art electroweak predictions. We use the most recent results for direct Hig
gs searches at LEP and Tevatron and the latest measurements of m_t and M_W. Example results are an estimation of the mass of the Higgs boson (M_H=116.3 +15.6 -1.3 GeV) and a forth-order result for the strong coupling constant (alpha_S(M_Z^2)=0.1193 +-0.0028(exp) +-0.0001(theo)). A fit of the oblique parameters (STU) to the electroweak data is performed, in order to constrain physics beyond the Standard Model. For instance, the parameter space of the Littlest Higgs Model with T-parity can be restricted via the oblique parameters. In addition, fit results for a model with an extended Higgs sector (2HDM) using mainly observables from the B and K physics are presented.
