Breaking flavor democracy with symmetric perturbations

Ghosh, Tathagata; Liao, Jiajun; Marfatia, Danny; Yanagida, Tsutomu T.

doi:10.1016/j.physletb.2018.08.062

Cited by 5 publications

(4 citation statements)

References 33 publications

(48 reference statements)

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“…( 30); instead, it is just an empirical guiding principle to help fix the basic texture of M x . How to explicitly break flavor democracy and S 3 symmetry is an open question [684,685,688,908,909,910,911,912,913,914], and hence whether the textures of ∆M l , ∆M D and ∆M R are appropriate or not can only be justified by their phenomenological consequences on the lepton mass spectra, flavor mixing angles, CP violation at low energies and even leptogenesis at the seesaw scale. Here we focus on the low-energy phenomenology by simply assuming ∆M R = 0 and [915]…”

Section: The Minimal Inverse Seesaw Scenariomentioning

confidence: 99%

Flavor structures of charged fermions and massive neutrinos

Xing

2019

Preprint

116

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Most of the free parameters in the Standard Model (SM) -a quantum field theory which has successfully elucidated the behaviors of strong, weak and electromagnetic interactions of all the known fundamental particles, come from the lepton and quark flavors. The discovery of neutrino oscillations has proved that the SM is incomplete, at least in its lepton sector; and thus the door of opportunity is opened to exploring new physics beyond the SM and solving a number of flavor puzzles. In this review article we give an overview of important progress made in understanding the mass spectra, flavor mixing patterns, CP-violating effects and underlying flavor structures of charged leptons, neutrinos and quarks in the past twenty years. After introducing the standard pictures of fermion mass generation, flavor mixing and CP violation in the SM extended with the presence of massive Dirac or Majorana neutrinos, we briefly summarize current experimental knowledge about the flavor parameters of quarks and leptons. Various ways of describing flavor mixing and CP violation are discussed, the renormalization-group evolution of flavor parameters is illuminated, and the matter effects on neutrino oscillations are interpreted. Taking account of possible extra neutrino species, we propose a standard parametrization of the 6 × 6 flavor mixing matrix and comment on the phenomenological aspects of heavy, keV-scale and light sterile neutrinos. We pay particular attention to those novel and essentially model-independent ideas or approaches regarding how to determine the Yukawa textures of Dirac fermions and the effective mass matrix of Majorana neutrinos, including simple discrete and continuous flavor symmetries. An outlook to the future development in unravelling the mysteries of flavor structures is also given.

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Section: The Minimal Inverse Seesaw Scenariomentioning

confidence: 99%

Flavor structures of charged fermions and massive neutrinos

Xing

2019

Preprint

116

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“…The sequential hierarchy among fermion masses, m 1 m 2 m 3 for the three generations of charged fermions, might be an indication of sequential breaking of residual symmetries. We will show that by first breaking S L 3 × S R 3 down to S L 2 × S R 2 [22,46] and then adding small random perturbations to break all global flavour symmetries, the observed sequential hierarchies can be naturally explained. In other words, the residual symmetries can further divide into different groups or separate at sequential steps.…”

Section: Introductionmentioning

confidence: 94%

“…Starting with democratic mass matrices for the quarks and charged leptons, and a diagonal Majorana neutrino mass matrix, we have V CKM = I and V PMNS = V † . Upon introducing perturbative corrections, the observed fermion masses and mixing angles can then be explained [17,46]. As global symmetries are not protected against the quantum gravity effects, the perturbations are naturally anarchical.…”

Section: Introductionmentioning

confidence: 99%

Broken democracy with intermediate S2×S2 residual symmetry and random perturbations

Barrie

Yanagida

2020

Physics Letters B

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The democratic mass matrix is an intriguing possibility for explaining the observed fermion mixings due to its inherent hierarchical mass eigenvalues and large mixing angles. Nevertheless, two of the three mass eigenvalues are zero if the flavor democracy is exact, in obvious contradiction with the experimental observations. One possibility is breaking the flavor democracy with anarchical perturbations as we proposed in an earlier work. However, even within the first two generations, the charged fermion masses are also hierarchical which may not be a coincidence. The democratic S L 3 × S R 3 symmetry of the three generations may first be broken down to an intermediate S L 2 × S R 2 symmetry among the first two generations to regulate the sequential hierarchies, followed by random perturbations, that generate the correct size of all measured observables. Unique predictions for neutrinoless double beta decay are also found. *

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“…This is the flavor "democratic" limit, which was studied in this context in [32], and which has a long and extensive literature (see e.g. [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]). However, Eq.…”

Section: Fermion Masses: Renormalizable Couplingsmentioning

confidence: 99%

Flavored gauge mediation with discrete non-Abelian symmetries

Everett

Garon

2018

Phys. Rev. D

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We explore the model building and phenomenology of flavored gauge-mediation models of supersymmetry breaking in which the electroweak Higgs doublets and the SUð2Þ messenger doublets are connected by a discrete non-Abelian symmetry. The embedding of the Higgs and messenger fields into representations of this non-Abelian Higgs-messenger symmetry results in specific relations between the Standard Model Yukawa couplings and the messenger-matter Yukawa interactions. Taking the concrete example of an S 3 Higgs-messenger symmetry, we demonstrate that, while the minimal implementation of this scenario suffers from a severe μ=B μ problem that is well known from ordinary gauge mediation, expanding the Higgs-messenger field content allows for the possibility that μ and B μ can be separately tuned, allowing for the possibility of phenomenologically viable models of the soft supersymmetrybreaking terms. We construct toy examples of this type that are consistent with the observed 125 GeV Higgs boson mass.

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Breaking flavor democracy with symmetric perturbations

Cited by 5 publications

References 33 publications

Flavor structures of charged fermions and massive neutrinos

Flavor structures of charged fermions and massive neutrinos

Broken democracy with intermediate S2×S2 residual symmetry and random perturbations

Flavored gauge mediation with discrete non-Abelian symmetries

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