Extra Generations, Discrepancies of Electroweak Precision Data and Mass of the Higgs
نویسنده
چکیده
The latest electroweak precision data are analyzed assuming the existence of the fourth generation of leptons (N,E) and quarks (U,D), which are not mixed with the known three generations. If all four new particles are heavier than Z boson, quality of the fit for the one new generation is as good as for the Standard Model. In the case of neutral leptons with masses around 50 GeV (“partially heavy extra generations”) the minimum of χ is between one and two extra generations. The predicted value of the higgs mass mH in the presence of the fourth generation can be made rather large. The quality of fits drastically improves when the data on band c-quark asymmetries and new NuTeV data on deep inelastic scattering are ignored.
منابع مشابه
26 1 v 1 2 4 Ju n 20 01 Precision measurements , extra quark - lepton generations and 50 GeV neutrinos
The existence of extra chiral generations with all fermions heavier than m Z is strongly disfavored by the precision electroweak data. However the data still allow a few extra generations if the neutral lep-tons have masses close to 50 GeV. Such heavy neutrino can be searched in the reaction e + e − → N ¯ N γ. Existence of 50 GeV neutrinos makes standard model Higgs boson invisible.
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