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arXiv · hep-ph/9403398

Flavour-Violating Charged Lepton Decays in Seesaw-Type Models

A. Ilakovac·A. Pilaftsis
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Abstract

Analytic expressions of lepton-flavour- and lepton-number-violating decays of charged leptons are derived in the context of general $SU(2)_L\otimes U(1)_Y$ seesaw scenarios that are motivated by grand unified theories (GUT's) or superstring models, in which left-handed and/or right-handed neutral singlets are present. Possible constraints imposed by cosmology and low-energy data are briefly discussed. The violation of the decoupling theorem in flavour-dependent graphs due to the presence of heavy neutral leptons of Dirac or Majorana nature is emphasized. Numerical estimates reveal that the decays $τ^-\to e^-e^-e^+$ or $τ^-\to e^-μ^-μ^+$ can be as large as $\sim 10^{-6}$, which may be observed in LEP experiments or other $τ$ factories.

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A. Ilakovac, A. Pilaftsis. 1999-01-04. Flavour-Violating Charged Lepton Decays in Seesaw-Type Models. https://doi.org/10.1016/0550-3213(94)00567-x

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