Extra generations and discrepancies of electroweak precision data
نویسندگان
چکیده
منابع مشابه
Extra Generations, Discrepancies of Electroweak Precision Data and Mass of the Higgs
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 heav...
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The existence of extra chiral generations with all fermions heavier than MZ is strongly disfavoured by the precision electroweak data. However the data are fitted nicely even by a few extra generations, if one allows neutral leptons to have masses close to 50 GeV. The data allow inclusion of one additional generation of heavy fermions in SUSY extension of Standard Model if chargino and neutrali...
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The recent data on Z boson decays and on the W mass are analyzed from the point of view of the possible existence of extra generations of leptons and quarks with masses > mZ=2. Present experimental accuracy is not su cient to exclude the existence of one extra generation of leptons and quarks, even with masses as low as 50 GeV. ) Permanent address: ITEP, Moscow 117259, Russia. ) On leave of abs...
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There are two aspects to the 1995 summer update of the combined preliminary electroweak data from LEP and SLC. On the one hand, agreement between experiments and the Standard Model (SM) has improved for the line-shape and the asymmetry data. The τ widths and asymmetries are now consistent with e– μ–τ universality, and all the asymmetry data including the left-right asymmetry from SLC are consis...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 2002
ISSN: 0370-2693
DOI: 10.1016/s0370-2693(02)01240-6