content_image/357520.jpg
localization, with an added bonus in the form of a built-in flavor protection that makes new physics at ∼ 2 − 3 TeV compatible with current EW precision and flavor data. 10 Given the success of GHU models in the quark sector, it is interesting to study their implications for the leptonic one. 

In this article, we have studied for the first time the implementation of a global A$_{4}$ sym- metry in models of GHU. The extra structure implied by the larger gauge symmetry results in some technical differences with respect to the simpler cases studied in the past. Thus, although LFV is generated at tree level, the global symmetry provides a strong enough fla- vor protection because a subgroup of the custodial symmetry required by EWPT naturally provides the necessary extra suppression. We have also investigated possible deviations from TBM (which is predicted at LO by the assumed discrete symmetry breaking) and the impli- cations of EWPT, LFV and neutrino masses and mixing on the spectrum of new resonances. This requires a precise enough determination of the masses and mixings of particles spreaded by many orders of magnitude, making the numerical analysis rather challenging. We must ensure that the many different types of corrections do not alter the necessary disparity of masses and mixings. In particular, the stringent bounds on LFV processes demands a pre- cise evaluation of the mixing between light and heavy leptons, because this mixing is what renders the one-loop contributions small enough. 

The model is compatible with all those experimental constraints for new gauge boson masses 

<img src='content_image/357520.jpg'>

Then, KK gluons could be accessible at the LHC [59] (see [60] for KK EW resonances). A new characteristic feature of our construction is the correlation between one-loop LFV (for instance, µ → eγ ) and the presence of light leptonic resonances in the spectrum. In order to keep LFV below current (and expected) experimental bounds, the A$_{4}$ breaking has to be relatively small. On the other hand, charged leptons masses are protected by this global flavor symmetry. Thus, the smaller its breaking is , the more composite τ$_{R}$ has to be in order to predict the correct τ mass. This in turn implies the existence of new leptonic resonances with masses of few hundreds of GeV and large couplings to τ$_{R}$ . They come in a full almost 

