GUT predictions for quark-lepton Yukawa coupling ratios with messenger masses from non-singlets

Self Cite

We propose a model of quark and lepton mixing based on the tetrahedral A 4 family symmetry with quark-lepton unification via the tetra-colour Pati-Salam gauge group SU(4) P S , together with SU(2) L × U(1) R . The "tetra-model" solves many of the flavour puzzles and remarkably gives ten predictions at leading order, including all six PMNS parameters. The Cabibbo angle is approximately given by θ C ≈ 1/4, due to the tetravacuum alignment (1, 4, 2), providing the Cabibbo connection between quark and lepton mixing. Higher order corrections are responsible for the smaller quark mixing angles and CP violation and provide corrections to the Cabibbo and lepton mixing angles and phases. The tetra-model involves an SO(10)-like pattern of Dirac and heavy right-handed neutrino masses, with the strong up-type quark mass hierarchy cancelling in the see-saw mechanism, leading to a normal hierarchy of neutrino masses with an atmospheric angle in the first octant, θ l 23 = 40 • ± 1 • , a solar angle θ l 12 = 34 • ± 1 • , a reactor angle θ l 13 = 9.0 • ± 0.5 • , depending on the ratio of neutrino masses m 2 /m 3 , and a Dirac CP violating oscillation phase δ l = 260 • ± 5 • .

Section: The Down Sectormentioning

confidence: 99%

“…The messenger mass for the first family arises from the coupling to an adjoint of SU(4) P S , Σ D ∼ (15, 1, 0), giving a Clebsch factor of 3 in the denominator [32]. The messenger mass for the second and third families arises from the PS singlet Σ ∼ (1, 1, 0) so no inverse Clebsch factors arise in these cases.…”

Section: The Down Sectormentioning

confidence: 99%

A model of quark and lepton mixing

King

2014

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“…A direct mass term of messenger fields M i Z iZi would in this case always show a up with a term of the form H 24 Z iZi . Such a contribution would inevitably spoil the desired CG factors [22] between Y d and Y T e as long as the mass and the adjoint VEV are not very hierarchical. To avoid this and still generate the desired operators the masses of the messenger fields that JHEP09(2014)141 give rise to W d in eq.…”

Section: A Model With Diagonalmentioning

confidence: 99%

“…This issue is generic in flavour models and can be resolved by constructing a specific UV completion of the effective operators, see [20,21] for mixing in lepton models, [11,22] for GUT relations, and for applications in (GUT) flavour models, e.g. [15][16][17].…”

Section: Yukawa Coupling Ratiosmentioning

confidence: 99%

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Towards predictive flavour models in SUSY SU(5) GUTs with doublet-triplet splitting

Antusch

Varzielas

Maurer

et al. 2014

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We discuss how the double missing partner mechanism solution to the doublettriplet splitting problem in four-dimensional supersymmetric SU(5) Grand Unified Theories (GUTs) can be combined with predictive models for the quark-lepton Yukawa coupling ratios at the GUT scale. It is argued that towards this goal a second SU(5) breaking Higgs field in the adjoint representation is very useful and we discuss all possible renormalizable superpotentials with two adjoint Higgs fields and calculate the constraints on the GUT scale and effective triplet mass from a two-loop gauge coupling unification analysis. Two explicit flavour models with different predictions for the GUT scale Yukawa sector are presented, including shaping symmetries and a renormalizable messenger sector. Towards calculating the rates for proton decay induced by the exchange of colour triplets, the required ClebschGordan coefficients for their couplings are calculated for the possible dimension five and six operators. They are provided in detailed tables in the appendix, together with additional helpful material for GUT flavour model building.

Generalised geometrical CP violation in a T ′ lepton flavour model

Girardi

Meroni

Petcov

et al. 2014

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Abstract:We analyse the interplay of generalised CP transformations and the nonAbelian discrete group T and use the semi-direct product G f = T H CP , as family symmetry acting in the lepton sector. The family symmetry is shown to be spontaneously broken in a geometrical manner. In the resulting flavour model, naturally small Majorana neutrino masses for the light active neutrinos are obtained through the type I see-saw mechanism. The known masses of the charged leptons, lepton mixing angles and the two neutrino mass squared differences are reproduced by the model with a good accuracy. The model allows for two neutrino mass spectra with normal ordering (NO) and one with inverted ordering (IO). For each of the three spectra the absolute scale of neutrino masses is predicted with relatively small uncertainty. The value of the Dirac CP violation (CPV) phase δ in the lepton mixing matrix is predicted to be δ ∼ = π/2 or 3π/2. Thus, the CP violating effects in neutrino oscillations are predicted to be maximal (given the values of the neutrino mixing angles) and experimentally observable. We present also predictions for the sum of the neutrino masses, for the Majorana CPV phases and for the effective Majorana mass in neutrinoless double beta decay. The predictions of the model can be tested in a variety of ongoing and future planned neutrino experiments.