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Flavor democracy broken in the fermion mass matrix by means of small perturbations can give rise to hierarchical fermion masses. We study the breaking of the $S^L_3 \times S^R_3$ symmetry associated with democratic mass matrices to a…

High Energy Physics - Phenomenology · Physics 2018-09-10 Tathagata Ghosh , Jiajun Liao , Danny Marfatia , Tsutomu T. Yanagida

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…

High Energy Physics - Phenomenology · Physics 2019-12-25 Neil D. Barrie , Shao-Feng Ge , Tsutomu T. Yanagida

We investigate the symmetry breaking pattern of the democratic mass matrix model, which leads to the small flavor mixing in quark sector and bi-large mixing in lepton sector. We present the symmetry breaking matrices in quark sector which…

High Energy Physics - Phenomenology · Physics 2007-05-23 Junpei Harada

We reexamine the democratic neutrino mixing ansatz, in which the mass matrices of charged leptons and Majorana neutrinos arise respectively from the explicit breaking of S(3)_L x S(3)_R and S(3) flavor symmetries. It is shown that a…

High Energy Physics - Phenomenology · Physics 2009-11-10 Harald Fritzsch , Zhi-zhong Xing

We propose a democratic-type neutrino mass matrix based on $Z_3$ symmetry. This mass matrix predicts the CP violation phase, $\delta=\pi/2$, and the mixing angle between the mass eigenstates $\nu_2$ and $\nu_3$, $\sin^2 \theta_{23}= \cos^2…

High Energy Physics - Phenomenology · Physics 2009-10-31 Kiko Fukuura , Takahiro Miura , Eiichi Takasugi , Masaki Yoshimura

We find using the minimal left-right symmetric model that the presence of leptonic CP violation can radiatively generate a strong CP phase at the one-loop level itself, which can be beyond the current bounds established by the neutron…

High Energy Physics - Phenomenology · Physics 2015-04-29 Ravi Kuchimanchi

Model-independent consequences of applying a generalized hidden horizontal Z_2 symmetry to the neutrino mass matrix are explored. The Dirac CP phase delta_D can be expressed in terms of the three mixing angles as 4 c_a s_a c_s s_s s_x cos…

High Energy Physics - Phenomenology · Physics 2011-08-11 Shao-Feng Ge , Duane A. Dicus , Wayne W. Repko

We update and improve past efforts to predict the leptonic Dirac CP-violating phase with models that predict perturbatively modified tribimaximal or bimaximal mixing. Simple perturbations are applied to both mixing patterns in the form of…

High Energy Physics - Phenomenology · Physics 2022-11-23 Yang Hwan Ahn , Sin Kyu Kang , Raymundo Ramos , Morimitsu Tanimoto

We propose a simple renormalizable model for the spontaneous CP violation based on $SU(2)_{L}\times U(1)_{Y}\times A_{4}$ symmetry in a radiative seesaw mechanism, which can be guaranteed by an extra $Z_{2}$ symmetry. In our model CP is…

High Energy Physics - Phenomenology · Physics 2013-07-17 Y. H. Ahn , Sin Kyu Kang , C. S. Kim

We present a model-independent analysis of Leptonic CP violation for some well known mixing scenarios. In particular, we considered modified schemes for Bimaximal(BM), Democratic(DC), Hexagonal(HG) and Tribimaixmal(TBM) mixing for our…

High Energy Physics - Phenomenology · Physics 2021-07-15 Sumit K. Garg

We show that there is a minimal discrete symmetry which leads to the extended flavour democracy scenario constraining the Dirac neutrino, the charged lepton and the Majorana neutrino mass term ($M_R$) to be all proportional to the…

High Energy Physics - Phenomenology · Physics 2009-11-07 G. C. Branco , J. I. Silva-Marcos

Non-zero leptonic CP phases in the neutrino sector are clear evidence for physics beyond the Standard Model and have many implications in particle physics and cosmology. Some clues to maximal Dirac CP violation $\delta_{CP}=3\pi/2$ are…

High Energy Physics - Phenomenology · Physics 2017-10-17 Ying Zhang

The exact democratic structure for the quark mass matrix, resulting from the action of the family symmetry group $A_{3L}\times A_{3R}$, is broken by the vaccum expectation values of heavy singlet fields appearing in non renormalizable…

High Energy Physics - Phenomenology · Physics 2007-05-23 Joaquim I. Silva-Marcos

We propose that leptonic CP violation arises from a breaking of the mu-tau exchange symmetry in the neutrino mass matrix which in turn is indicated by the near maximal atmospheric neutrino mixing and the near zero \theta_{13}. We find that…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. N. Mohapatra , W. Rodejohann

We derive predictions for the Dirac phase $\delta$ present in the $3\times 3$ unitary neutrino mixing matrix $U = U_e^{\dagger} \, U_{\nu}$, where $U_e$ and $U_{\nu}$ are $3\times 3$ unitary matrices which arise from the diagonalisation,…

High Energy Physics - Phenomenology · Physics 2015-11-10 I. Girardi , S. T. Petcov , A. V. Titov

It is known that the imposition of a class of residual $Z_2\times Z_2$ symmetries on the neutrino mass matrix $M_\nu$ and a residual symmetry $Z_n$ ($n\geq 3$) on the Hermitian combination $M_lM_l^\dagger$ of the charged lepton mass matrix…

High Energy Physics - Phenomenology · Physics 2018-01-10 Anjan S. Joshipura

The democracy of quark flavors is a well-motivated flavor symmetry, but it must be properly broken in order to explain the observed quark mass spectrum and flavor mixing pattern. We reconstruct the texture of flavor democracy breaking and…

High Energy Physics - Phenomenology · Physics 2017-10-04 Harald Fritzsch , Zhi-zhong Xing , Di Zhang

We explore the implications of recent results relating the Dirac CP-violating phase to predicted and measured leptonic mixing angles within a standard set of theoretical scenarios in which charged lepton corrections are responsible for…

High Energy Physics - Phenomenology · Physics 2018-05-29 Luis A. Delgadillo , Lisa L. Everett , Raymundo Ramos , Alexander J. Stuart

We show that large leptonic mixing occurs most naturally in the framework of the Sandard Model just by adding a fourth generation. One can then construct a small $Z_4$ discrete symmetry, instead of the large $S_{4L}\times S_{4R}$, which…

High Energy Physics - Phenomenology · Physics 2010-02-03 Joaquim I. Silva-Marcos

Oscillations of the Dirac neutrinos of three generations in vacuum are considered with allowance made for the effect of the CP-violating leptonic phase (analogue of the quark CP phase) in the lepton mixing matrix. The general formulas for…

High Energy Physics - Phenomenology · Physics 2009-11-07 D. A. Ryzhikh , K. A. Ter-Martirosyan
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