Neutrinos: Summarizing the State-of-the-Art

Valle, J. W. F.

doi:10.1007/978-3-642-55739-2_38

Cited by 4 publications

(11 citation statements)

References 124 publications

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“…26) This LMA solution for the solar neutrino problem gives the best to the present experimental data. 27) Finally, we would like to make a comment on an interesting feature of this scenario, which is also seen in the SO(10) model. 14) In addition to Eq.…”

Section: A Higgs Field That Includes the Higgs Doublets: H(27)mentioning

confidence: 90%

“…Throughout this paper we denote all the superfields with uppercase letters and their anomalous U (1) A charges with the corresponding lowercase letters. Assigning negative R-parity to the ordinary matter Ψ i (27), as usual, and using a field Θ with charge −1, the U (1) A invariant superpotential for low energy Yukawa terms becomes…”

Section: A Higgs Field That Includes the Higgs Doublets: H(27)mentioning

confidence: 99%

“…So here let us explain how the twisting family structure arises in the E 6 unification. In order to do this, it is enough to introduce the following Higgs fields, * ) which are necessary to determine the mass matrices of matter multiplets Ψ i (27), whose U (1) A charges are denoted as…”

Section: §1 Introductionmentioning

confidence: 99%

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E6 Unification with Bi-Large Neutrino Mixing

Bandō

Maekawa

2001

Progress of Theoretical Physics

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The scenario of SO(10) grand unified theory (GUT) proposed by one of the authors is extended to E6 unification. This gives realistic quark and lepton mass matrices. In the neutrino sector, the model reproduces the large mixing angle (LMA) MSW solution as well as the large mixing angle for the atmospheric neutrino anomaly. In this model, the righthanded down quark and the left-handed lepton of the first and second generations belong to a single multiplet 27. This causes natural suppression of the flavour changing neutral current(FCNC). * ) interesting features:1. The doublet-triplet (DT) splitting is realized using the Dimopoulos-Wilczek mechanism. 2. Proton decay via the dimension-five operator is suppressed. 3. Realistic quark and lepton mass matrices can be obtained in a simple way. In particular, in the neutrino sector, bi-large neutrino mixing is realized. 4. The symmetry breaking scales are determined by the anomalous U (1) A charges. 5. The mass spectrum of the super heavy particles is fixed by the anomalous U (1) A charges. As a consequence of the above features, the fact that the GUT scale is smaller than the Planck scale leads to modification of the undesirable GUT relation between the Yukawa couplings y µ = y s (and also y e = y d ) while preserving the relation y τ = y b . Moreover, it is remarkable that the interaction is generic; all the interactions that are allowed by the symmetry are taken into account. Therefore, once we fix the field contents with their quantum numbers, all the interactions are determined, except coefficients of order 1.The anomalous U (1) A gauge symmetry, 15) whose anomaly is cancelled by the Green-Schwarz mechanism, 16) plays an essential role in explaining the DT splitting mechanism at the unification scale as well as in reproducing Yukawa hierarchies. 17), 18), 19) Also, bi-large neutrino mixing is naturally obtained by choosing the 10 representation with an appropriate U (1) A charge, in addition to the three family 16 representations. This anomalous U (1) A is a powerful tool not only to reproduce DT splitting but also to determine the GUT breaking scales.This paper aims to show further that the above SO(10) model is naturally extended to E 6 GUT, in which the additional field 10 of SO(10) is included in a chiral multiplet 27 of E 6 . In order to realize this scenario, it is important to introduce the concept of "twisting family structure" in the E 6 unified model. 11) Under the SO(10) group, we know that 10 and 5 of SU (5) are combined into 16 of SO(10). Usually, each family belongs to 16. In this framework, however, it is not easy to reproduce the large Maki-Nakagawa-Sakata (MNS) 20) mixing and small Cabbibo-Kobayashi-Maskawa (CKM) 21) mixing. A promising way to reproduce this is to introduce other multiplets, 10 of SO(10), in addition to the usual 3 × 16 multiplets. 10) Since 10 of SO(10) is decomposed into 5(10) and 5(10) of SU (5), one of the fields 5(16) can be replaced by this 5(10). Such a replacement is essential to reproduce large MNS mixing, preserving small CK...

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Section: A Higgs Field That Includes the Higgs Doublets: H(27)mentioning

confidence: 90%

Section: A Higgs Field That Includes the Higgs Doublets: H(27)mentioning

confidence: 99%

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E6 Unification with Bi-Large Neutrino Mixing

Bandō

Maekawa

2001

Progress of Theoretical Physics

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“…This is not possible since different particles all have different gauge quantum numbers. 5 In principle we are allowed to do this since the cancellation of the FI D-term only imposes…”

Section: Mass Matrices After the Fayet-iliopoulos Breakingmentioning

confidence: 99%

“…In addition one would like to understand the mixings and hierarchies of neutrinos. The global analysis of solar, atmospheric and reactor data [5] indicates that they have masses given by ∆m 2 21 ≈ 2.4 × 10 −5 to 2.4 × 10 −4 eV 2 , ∆m 2 32 ≈ 1.4 × 10 −3 to 6 × 10 −3 eV 2 , (3) and a Maki-Nakagawa-Sakata (MNS) weak coupling matrix [6] with the charged leptons [5]:…”

Section: Introductionmentioning

confidence: 99%

Quark and lepton masses and mixing angles from superstring constructions

Abel

Muñoz

2003

J. High Energy Phys.

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We show that the observed structure of quark and lepton masses and mixing angles can arise entirely geometrically from superstring constructions, at the renormalizable level. The model we consider is a Z 3 orbifold compactification of heterotic string with two Wilson lines, where three families of particles of SU(3) c × SU(2) L × U(1) Y , including Higgses, are automatically present. In orbifold models, Yukawa couplings can be calculated explicitly, and it is known that they get exponential suppression factors depending on the distance between the fixed points to which the fields are attached. We find that in the Z 3 case, the quark and charged-lepton mass hierarchies can easily be obtained for reasonable values of the three moduli determining the radii of the compactified space, T i ∼ 1. For the neutrinos, due to the smallness of their Dirac masses, the required scale for the see-saw mechanism to give the correct masses is found to be within reach of the electroweak scale. Finally, we find that one of the small number of possibilities for quark and lepton mass matrices yields consistent results for the mixing angles and the weak CP violation phase. Although our scheme relies on the mixing between fields due to Fayet-Iliopoulos breaking, it is considerably more predictive than alternative models of flavour.

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Neutrino Masses, Anomalous U(1) Gauge Symmetry and Doublet-Triplet Splitting

Maekawa

2001

Progress of Theoretical Physics

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We propose an attractive scenario of grand unified theories in which doublet-triplet splitting is naturally realized in SO(10) unification using the Dimopoulos-Wilczek mechanism. The anomalous U (1) A gauge symmetry plays an essential role in the doublet-triplet splitting mechanism. It is interesting that the anomalous U (1) A charges determine the unification scale and mass spectrum of additional particles, as well as the order of the Yukawa couplings of quarks and leptons. For the neutrino sector, bi-maximal mixing angles are naturally obtained, and proton decay via dimension 5 operators is suppressed. It is suggestive that the anomalous U (1) A gauge symmetry motivated by superstring theory effectively solves the two biggest problems in grand unified theories, the fermion mass hierarchy problem and doublet-triplet splitting problem. * )

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Neutrinos: Summarizing the State-of-the-Art

Cited by 4 publications

References 124 publications

E6 Unification with Bi-Large Neutrino Mixing

E6 Unification with Bi-Large Neutrino Mixing

Quark and lepton masses and mixing angles from superstring constructions

Neutrino Masses, Anomalous U(1) Gauge Symmetry and Doublet-Triplet Splitting

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