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Non-vanishing U_{e3} has been theoretically related to a certain flavor symmetry breaking in the neutrino sector. We propose a scenario to break the mu-tau symmetry so as to accommodate the non-vanishing U_{e3}. Our scenario is constructed…

High Energy Physics - Phenomenology · Physics 2011-07-19 Y. H. Ahn , Sin Kyu Kang , C. S. Kim , Jake Lee

Amid the uncertainty regarding the fundamental nature of neutrinos, we adhere to the Dirac description, and construct a model in the framework of $\Delta(27)$ symmetry. The model successfully accounts for the hierarchical patterns of both…

High Energy Physics - Phenomenology · Physics 2025-01-23 Manash Dey , Subhankar Roy

The smallness of the 1-3 lepton mixing angle $\theta_{13}$ and of the neutrino mass-squared-difference ratio $\Delta m^2_{12}/\Delta m^2_{23}$ can be understood as the departure from a common limit where they both vanish. We discuss in…

High Energy Physics - Phenomenology · Physics 2008-11-26 Michele Frigerio , Ernest Ma

Lepton mixing patterns from the modular group $PSL_2(7)$ with generalised CP symmetries are studied. The residual symmetries in both charged leptons and neutrinos sector are $Z_{2}\times CP$. Seven types of mixing patterns at the $3\sigma$…

High Energy Physics - Phenomenology · Physics 2020-02-04 Shu-Jun Rong

We diagonalize Majorana neutrino mass matrix with the help of PMNS matrix and obtain analytical relations between the mass matrix elements and mixing parameters, viz., three mixing angles- $\theta_{12}, \theta_{23}, \theta_{13}$ and Dirac…

High Energy Physics - Phenomenology · Physics 2019-05-21 Chandan Duarah

A model for neutrino masses and mixing is devised appointing the see-saw mechanism. The proffered model is fabricated with a combination of Type -I and Type-II see-saw contributions of which the latter dominates. The scalars and the leptons…

High Energy Physics - Phenomenology · Physics 2018-10-24 Soumita Pramanick

We consider the see-saw mechanism for hierarchical Dirac and Majorana neutrino mass matrices m_D and M_R, including the CP violating phases. Simple arguments about the structure of the neutrino mass matrix and the requirement of successful…

High Energy Physics - Phenomenology · Physics 2011-07-19 Werner Rodejohann

The concepts of effective and dynamical neutrino mixing matrices are introduced in order to describe the behavior of neutrinos in matter. The former relates weak eigenstates to mass eigenstates, whereas the latter relates weak eigenstates…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. D. Kim , C. W. Kim , Jewan Kim , Dae-Gyu Lee

In the vanilla type-I seesaw leptogenesis scenario, CP violation required to generate the lepton asymmetries in the heavy Majorana neutrino decays stem from complex Dirac-type Yukawa couplings. In this paper we explore the case in which…

High Energy Physics - Phenomenology · Physics 2023-01-25 D. M. Barreiros , H. B. Câmara , R. G. Felipe , F. R. Joaquim

Assuming three generations of Majorana neutrinos, we study the different mixing patterns that arise from the non-trivial breaking of the flavor group A5 and CP to the residual symmetries Z3, Z5 or Z2 x Z2 in the charged lepton and to Z2 x…

High Energy Physics - Phenomenology · Physics 2015-09-30 Andrea Di Iura , Claudia Hagedorn , Davide Meloni

We discuss constraints on a scenario of almost degenerate three-flavor neutrinos imposed by the solar and the atmospheric neutrino anomalies, hot dark matter, and neutrinoless double $\beta$ decays. It is found that in the Majorana version…

High Energy Physics - Phenomenology · Physics 2014-11-17 Hisakazu Minakata , Osamu Yasuda

We propose an $A_4$ modular invariant flavor model of leptons, in which both CP and modular symmetries are broken spontaneously by the vacuum expectation value of the modulus $\tau$. The value of the modulus $\tau$ is restricted by the…

High Energy Physics - Phenomenology · Physics 2021-08-18 Hiroshi Okada , Yusuke Shimizu , Morimitsu Tanimoto , Takahiro Yoshida

We discuss the energy scale profile of the bi-maximal mixing which is given at the GUT energy scale in the minimal SUSY model, associated with an assumption that Y_nu^dagger Y_nu is diagonal, where Y_nu is the neutrino-Yukawa coupling…

High Energy Physics - Phenomenology · Physics 2009-11-10 Tetsuo Shindou , Eiichi Takasugi

We study the freeze-in scenario of leptogenesis via oscillations within the type-I seesaw model with two quasi-degenerate heavy Majorana neutrinos $N_{1,\,2}$ having masses $M_2 > M_1 \sim (0.1-100)\,\text{GeV}$, $(M_2-M_1)/M_1 \ll 1$,…

High Energy Physics - Phenomenology · Physics 2023-11-09 Alessandro Granelli , Silvia Pascoli , Serguey T. Petcov

The observed leptonic mixing pattern could be explained by the presence of a discrete flavour symmetry broken into residual subgroups at low energies. In this scenario, a residual generalised CP symmetry allows the parameters of the PMNS…

High Energy Physics - Phenomenology · Physics 2015-11-25 Peter Ballett , Silvia Pascoli , Jessica Turner

We discuss the conditions for a non-vanishing Dirac phase \delta and mixing angle \theta_{13}, sources of CP violation in neutrino oscillations, to be uniquely responsible for the observed matter-antimatter asymmetry of the universe through…

High Energy Physics - Phenomenology · Physics 2008-11-26 Alexey Anisimov , Steve Blanchet , Pasquale Di Bari

We present a systematic procedure to establish a connection between complex neutrino mass matrix textures and experimental observables, including the Dirac CP phase. In addition, we illustrate how future experimental measurements affect the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Walter Winter

A solution for the neutrino mass and mixing pattern is proposed which is compatible with all available experimental data on neutrino oscillations. This solution involves Majorana neutrinos of the pseudo-Dirac type, i.e. m_Majorana <<…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. Geiser

We discussed the scenario that a discrete flavor group combined with CP symmetry is broken to $Z_2\times CP$ in both neutrino and charged lepton sectors. All lepton mixing angles and CP violation phases are predicted to depend on two free…

High Energy Physics - Phenomenology · Physics 2018-04-04 Cai-Chang Li , Jun-Nan Lu , Gui-Jun Ding

A universal seesaw mass matrix model, which gives successful description of quark mass matrix in terms of lepton masses, yields three "sterile" neutrinos \nu^s_{i}, which compose pseudo-Dirac neutrinos \nu_{i\pm}^{ps}\simeq (\nu_{i} \pm…

High Energy Physics - Phenomenology · Physics 2009-10-31 Yoshio Koide , Hideo Fusaoka