1993/07/14 by Enrico Nardi, Nardi, Enrico
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9307267
(Invited talk at the ``Workshop on Physics and Experiments at Linear e+e- Colliders'' Waikoloa, Hawai, April 26-30, 1993) Plain Tex, 10 pages, + 1 PostScript figure appended after \bye (and available upon request), UM-TH 93--14
arxiv created 1993/07/14 · arxiv updated 2009/11/30
The constraints on the mixing angles of the standard fermions with new heavy particles that can appear in many extensions of the electroweak theory are reviewed. Some emphasis is put in distinguishing the effects of a mixing with new states which transform in a non-canonical way with respect to SU(2)× U(1) (left-handed singlets or right-handed doublets), from the effects of a mixing with new states with standard quantum number assignments. Constraints from flavor changing neutral current processes, as well as from flavor diagonal and charged current experimental data are considered. New limits for lepton flavor violating mixings are presented. By using the most recent results on the τ mass, lifetime and branching ratios, updated limits on the mixing parameters of the τ neutrino are derived. These limits are improved up to a factor of 3, and no signals of deviation from the standard model predictions are found. Limits on the mass of a Z1 gauge boson from E6, from the absence of muon number violating processes are briefly discussed as well.