On-shell renormalization of the mixing matrices in Majorana neutrino theories
Abstract We generalize a recently proposed on-shell approach to renormalize the Cabibbo–Kobayashi–Maskawa quark-mixing matrix to the case of an extended leptonic sector that includes Dirac and Majorana neutrinos in the framework of the seesaw mechanism. An important property of this formulation is the gauge independence of both the renormalized and bare lepton mixing matrices. Also, the texture zero in the neutrino mass matrix is preserved.
Lepton-flavor-violating decays of the Z boson in a left-right supersymmetric model.
We study the one-loop supersymmetric contributions to lepton-flavor violating Z -boson decays in a fully left-right symmetric model. In addition to right-handed scalar neutrinos, the decays could receive important contributions from doubly-charged triplet Higgsinos which couple to leptons only. We find that the decay widths reach present experimental bounds and discuss mass constraints for the contributing supersymmetric partners.
Lepton-flavor-violating decays of Z0 and tau.
We examine a class of extended electroweak models in which lepton flavors are violated due to neutral gauge bosons which do not couple universally to the fermion generations. It is shown that the decays Z/sup 0/..-->..tau..mu.. and tau..--> mu..+(..mu..mu-bar,..pi../sup 0/,. . .) can occur with sizable branching ratios (approx.10/sup -7/). Relations amongst these decay modes are also obtained.