CP violation and Leptogenesis in models with Minimal Lepton Flavour Violation

Abstract

We investigate the viability of leptogenesis in models with three heavy right-handed neutrinos, where the charged-lepton and the neutrino Yukawa couplings are the only irreducible sources of lepton-flavour symmetry breaking (Minimal Lepton Flavour Violation hypothesis). We show that in this framework a specific type of resonant leptogenesis can be successfully accomplished. For natural values of the free parameters, this mechanism requires a high right-handed neutrino mass scale ($M_\nu \gsim 10^{12}$ GeV). By means of a general effective field theory approach, we analyse the impact of the CP violating phases responsible for leptogenesis on the low-energy FCNC observables and derive bounds on the scale of flavour violating new physics interactions. As a result of the high value of the scale of total lepton-number violation, in this class of models the $\mu\to e\gamma$ decay is expected to be close to the present exclusion limit (under the additional assumption of new particles carrying lepton flavour at the TeV scale).