Lepton Flavour Violation in a Left-Right Symmetric Model

We consider in this paper a Left-Right symmetric gauge model in which a global lepton-number-like symmetry is introduced and broken spontaneously at a scale that could be as low as 10^4 GeV or so. The corresponding physical Nambu-Goldstone boson, which we call majoron and denote J, can have tree-level flavour-violating couplings to the charged fermions, leading to sizeable majoron-emitting lepton-flavour-violating weak decays. We consider explicitly a leptonic variant of the model and show that the branching ratios for \mu -> e+J, \tau -> e + J and \tau -> \mu + J decays can be large enough to fall within the sensitivities of future \mu and \tau factories. On the other hand the left-right gauge symmetry breaking scale may be as low as few TeV.Comment: LaTeX, 16 pages, 3 PS figures, uses JHEP.cls, published versio

Predicting charged lepton flavor violation from 3-3-1 gauge symmetry

The simplest realization of the inverse seesaw mechanism in a $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ gauge theory offers striking flavor correlations between rare charged lepton flavor violating decays and the measured neutrino oscillations parameters. The predictions follow from the gauge structure itself without the need for any flavor symmetry. Such tight complementarity between charged lepton flavor violation and oscillations renders the scenario strictly testable.Comment: 7 pages, 2 figures; v2: discussion extended. Matches version published in PR