Unified theories with U(2) flavor symmetry

Barbieri, Riccardo; Hall, Lawrence J.; Raby, Stuart; Romanino, Andrea

doi:10.1016/s0550-3213(97)00134-x

Cited by 160 publications

(231 citation statements)

References 53 publications

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“…There are several SO(10) models, in both renormalizable [25][26][27][28][29][30][31][32][33][34][35][36][37][38] and nonrenormalizable [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] versions (see [56,57] for reviews), where new ingredients are added either to reduce the number of free parameters or to reduce their relevant range. In the first case the predictability of the model is increased, while in the second case the model becomes more natural.…”

Section: Jhep09(2014)095mentioning

confidence: 99%

Order and anarchy hand in hand in 5D SO(10)

Feruglio

Patel

Vicino

2014

J. High Energ. Phys.

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We update a five-dimensional SO(10) grand unified model of fermion masses and mixing angles originally proposed by Kitano and Li. In our setup Yukawa couplings are anarchical and quark and lepton sectors are diversified by the profiles of the fermion zero modes in the extra dimension. The breaking of SO(10) down to SU(5)×U(1) X provides the key parameter that distinguishes the profiles of the different SU(5) components inside the same 16 representation. With respect to the original version of the model, we extend the Higgs sector to explicitly solve the doublet-triplet splitting problem through the missing partner mechanism and we perform a fit to an idealized set of data. By scanning the Yukawa couplings of the model we find that, for large tan β, both normal and inverted ordered neutrino spectrum can be accommodated. However, while the case of inverted order requires a severe fine tuning of the Yukawa parameters, the normal ordering is compatible with an anarchical distribution of Yukawa couplings. Thus, in a natural portion of the parameter space, the model predicts a normal ordered neutrino spectrum, the lightest neutrino mass below 5 meV, and |m ββ | in the range 0.1-5 meV. No particular preference is found for the Dirac CP phase in the lepton sector while the right-handed neutrino masses are too small to explain the baryon asymmetry of the universe through thermal leptogenesis.

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Section: Jhep09(2014)095mentioning

confidence: 99%

Order and anarchy hand in hand in 5D SO(10)

Feruglio

Patel

Vicino

2014

J. High Energ. Phys.

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“…This model can be considered as a descendant of the model by Barbieri et al, [34], with the two lightest generations in a doublet of U(2) and the third generation in a singlet. In fact, S 3 , the permutation group of 3 objects, is a discrete subgroup of SO(3) (and SU (2) is the covering group of SO (3)) with inequivalent irreducible representations 2, 1 and 1'.…”

Section: Jhep03(2011)133 6 Comparison With Other So(10) Modelsmentioning

confidence: 99%

Different SO(10) paths to fermion masses and mixings

Altarelli

Blankenburg

2011

J. High Energ. Phys.

137

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Recently SO(10) models with type-II see-saw dominance have been proposed as a promising framework for obtaining Grand Unification theories with approximate Tribimaximal (TB) mixing in the neutrino sector. We make a general study of SO(10) models with type-II see-saw dominance and show that an excellent fit can be obtained for fermion masses and mixings, also including the neutrino sector. To make this statement more significant we compare the performance of type-II see-saw dominance models in fitting the fermion masses and mixings with more conventional models which have no built-in TB mixing in the neutrino sector. For a fair comparison the same input data and fitting procedure is adopted for all different theories. We find that the type-II dominance models lead to an excellent fit, comparable with the best among the available models, but the tight structure of this framework implies a significantly larger amount of fine tuning with respect to other approaches.

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“…The I gives (under the assumption that the k's are much bigger than all the other vevs) the top, bottom, and tau masses, and the hierarchy between these and the other masses is given by the Σ/k and q/k ratios. Maybe it is possible to justify our ansatz from a symmetry bigger than S 2 which constrains the matrix I (such as a modification of the U (2) in [3]) but we will not investigate this point in this paper. For simplicity, we rewrite the ∆s (and equivalently the Φ) matrices as…”

Section: Our Ansatzmentioning

confidence: 99%

“…These motivations suggest us to consider discrete symmetries in extensions of the unified version of the SM. In literature are investigated both unified models based on extension of the standard model such us SO (10) [2] symmetry with [3] or without [4] continuous flavor symmetries, and not unified models based on discrete symmetries [5]. Although some of them appear to be promising in understanding the flavor physics and unification [6] we are still far from an unitarity vision of the flavor problem [7].…”

Section: Introductionmentioning

confidence: 99%

The Flavor Physics in Unified Gauge Theory from an S3 × P Discrete Symmetry

Morisi

Picariello

2006

Int J Theor Phys

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We investigate the phenomenological implication of the discrete symmetry S 3 × P on flavor physics in SO(10) unified theory. We construct a minimal renormalizable model which reproduce all the masses and mixing angle of both quarks and leptons. As usually the SO(10) symmetry gives up to relations between the down sector and the charged lepton masses. The underlining discrete symmetry gives a contribution (from the charged lepton sector) to the PMNS mixing matrix which is bimaximal. This gives a strong correlation between the down quark and charged lepton masses, and the lepton mixing angles. We obtain that the small entries V ub , V cb , V td , and V ts in the CKM matrix are related to the small value of the ratio δm 2 sol /δm 2 atm : they come from both the S 3 × P structure of our model and the small ratio of the other quark masses with respect to m t .

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Unified theories with U(2) flavor symmetry

Cited by 160 publications

References 53 publications

Order and anarchy hand in hand in 5D SO(10)

Order and anarchy hand in hand in 5D SO(10)

Different SO(10) paths to fermion masses and mixings

The Flavor Physics in Unified Gauge Theory from an S3 × P Discrete Symmetry

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