Abstract

We present a non-minimal renormalizable SUSY $$SU(5)$$ model, with extended Higgs sector and right-handed neutrinos, where the flavor sector exhibits a $$Q_{6}$$ flavor symmetry. We analyzed the simplest version of this model, in which R-parity is conserved and the right-handed neutrino masses in the flavor doublet are considered with and without degeneracy. We find the generic form of the mass matrices both in the quark and lepton sectors. We reproduce, according to current data, the mixing in the CKM matrix. In the leptonic sector, in the general case where the right-handed neutrino masses are not degenerate, we find that the values for the solar, atmospheric, and reactor mixing angles are in very good agreement with the experimental data, both for a normal and an inverted hierarchy. In the particular case where the right-handed neutrinos masses are degenerate, the model predicts a strong inverted hierarchy spectrum and a sum rule among the neutrino masses. In this case the atmospheric and solar angles are in very good agreement with experimental data, and the reactor one is different from zero, albeit too small ( $$\theta ^{\ell ^{\mathrm{th}}}_{13} \sim 3.38^{\circ } $$ ). This value constitutes a lower bound for $$\theta _{13}$$ in the general case. We also find the range of the values for the neutrino masses in each case.

Highlights

  • Understanding the flavor sector of the Standard Model (SM) has been a puzzle for a long time, due to the large differences in the Yukawa couplings of the different fermions

  • We present a non-minimal renormalizable SUSY SU (5) model, with extended Higgs sector and right-handed neutrinos, where the flavor sector exhibits a Q6 flavor symmetry

  • We find the generic form of the mass matrices both in the quark and lepton sectors

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Summary

Introduction

Understanding the flavor sector of the Standard Model (SM) has been a puzzle for a long time, due to the large differences in the Yukawa couplings of the different fermions. The SUSY SU (5) matter content provides the tools to accommodate masses and mixings via the extension of the Higgs scalar sector, gauge coupling unification may be compromised This philosophy has been worked out with success in non-supersymmetric [48,49,50] and supersymmetric [13,14,15,16,17] scenarios, where the concept of flavor has been extended to the Higgs sector. The need to extend the scalar sector is evident in order to accommodate masses and mixings for quarks and leptons without breaking explicitly the flavor symmetry, so that three families of H u and H d 5-plets are introduced. As we will show later on, when we relate mν with a matrix with two texture zeros of class I [50,57,58,59,60], the number of real effective free parameters is reduced to only four

Quark and lepton masses
Quark and lepton mixings
The masses of the right-handed neutrinos with degeneration
CKM mixing matrix
The masses of right-handed neutrinos with degeneration
The masses of right-handed neutrinos without degeneration
Outlook and remarks
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