SO(10) \xd7 S4 grand unified theory of flavour and leptogenesis

Francisco J De Anda,Elena Perdomo,Stephen F King

doi:10.1007/jhep12(2017)075

Abstract

We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S4, under which the unified three quark and lepton 16-plets are unified into a single triplet 3′. The model involves a further discrete group ℤ4R × ℤ43 which controls the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum alignment is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay is shown to be under control. The Yukawa matrices are derived in detail, from renormalisable diagrams, and neutrino masses emerge from the type I seesaw mechanism. A full numerical fit is performed with 15 input parameters generating 19 presently constrained observables, taking into account supersymmetry threshold corrections. The model predicts a normal neutrino mass ordering with a CP oscillation phase of 260°, an atmospheric angle in the first octant and neutrinoless double beta decay with mββ = 11 meV. We discuss N2 leptogenesis, which fixes the second right-handed neutrino mass to be M2 ≃ 2 × 1011 GeV, in the natural range predicted by the model.

Highlights

We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S4, under which the unified three quark and lepton
We prefer the simpler CSD2 [75, 76] vacuum alignment, which, in conjunction with small charged lepton corrections arising from the SO(10) structure of Yukawa matrices, is capable of yielding the desired reactor angle
The flavon vacuum alignment potential is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay are shown to be under control

Summary

Introduction

We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S4 , under which the unified three quark and lepton. Note that we are performing the numerical fit in terms of the effective neutrino mass parameters μi defined in eq (7.19).

Results

Conclusion