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Precision measurements, extra quark-lepton generations and 50 GeV neutrinos

V. Novikov
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Abstract

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 leptons have masses close to 50 GeV. Such heavy neutrino can be searched in the reaction $e^+ e^- \to N\bar{N}γ$. Existence of 50 GeV neutrinos makes standard model Higgs boson invisible.

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V. Novikov. 2001-06-24. Precision measurements, extra quark-lepton generations and 50 GeV neutrinos. https://arxiv.org/abs/hep-ph/0106261

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