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Related papers: Dirac Lepton Angle Matrix v.s. Majorana Lepton Ang…

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In the framework of three light Majorana neutrinos, we show how to reconstruct, through the use of 3 x 3 unitarity, the full PMNS matrix from six independent Majorana-type phases. In particular, we express the strength of Dirac-type CP…

High Energy Physics - Phenomenology · Physics 2010-04-21 Gustavo C. Branco , M. N. Rebelo

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 exchange symmetry between the muon neutrino and the tau neutrino for the neutrino mass matrix has been very useful in understanding the near maximal atmospheric neutrino mixing angle. However, this symmetry can not be imposed at the…

High Energy Physics - Phenomenology · Physics 2015-06-17 Shreyashi Chakdar , Kirtiman Ghosh , S. Nandi

We review recent developments in models of neutrino masses and mixing. Emphases are given to models based on finite group family symmetries from which the tri-bimaximal neutrino mixing can arise. In particular, we describe one recent model…

High Energy Physics - Phenomenology · Physics 2015-03-17 Mu-Chun Chen , K. T. Mahanthappa

We study mixing and CP violation of three left-handed Majorana neutrinos in the limit of exactly degenerate masses, identify the weak-basis invariant relevant for CP violation and show that the leptonic mixing matrix is parametrized only by…

High Energy Physics - Phenomenology · Physics 2009-10-31 G. C. Branco , M. N. Rebelo , J. I. Silva-Marcos

In the canonical seesaw mechanism, the strengths of charged-current interactions for light and heavy Majorana neutrinos are described respectively by the $3\times 3$ matrices $U$ and $R$ that are correlated with each other via the exact…

High Energy Physics - Phenomenology · Physics 2025-08-05 Zhi-zhong Xing

We study the minimal seesaw model, where two right-handed Majorana neutrinos are introduced, focusing on the CP violating phase. In addition, we take the trimaximal mixing pattern for the neutrino flavor where the charged lepton mass matrix…

High Energy Physics - Phenomenology · Physics 2018-01-17 Yusuke Shimizu , Kenta Takagi , Morimitsu Tanimoto

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

General Majorana neutrino mass matrix is complex symmetric and for three generations of neutrinos it contains 12 real parameters. We diagonalize this general neutrino mass matrix and express the three neutrino masses, three mixing angles,…

High Energy Physics - Phenomenology · Physics 2015-06-16 Biswajit Adhikary , Mainak Chakraborty , Ambar Ghosal

Taking into account the recent progress in the understanding of the lepton flavour effects in leptogenesis, we investigate in detail the possibility that the CP-violation necessary for the generation of the baryon asymmetry of the Universe…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Pascoli , S. T. Petcov , Antonio Riotto

We propose that the observed large leptonic mixing may just reflect a quasidegeneracy of three Majorana neutrinos. The limit of exact degeneracy of Majorana neutrinos is not trivial, as leptonic mixing and even CP violation may occur. We…

High Energy Physics - Phenomenology · Physics 2015-02-23 G. C. Branco , M. N. Rebelo , J. I. Silva-Marcos , Daniel Wegman

We study mixing of the Dirac neutrinos in the residual symmetries approach. The key difference from the Majorana case is that the Dirac mass matrix may have larger symmetries: $G_\nu=\mathbf{Z}_{n}$ with $n\geq3$. The symmetry group…

High Energy Physics - Phenomenology · Physics 2015-12-02 Arman Esmaili , Alexei Yu. Smirnov

A model independent analysis of the leptonic Dirac CP-violating phase ({\delta}) is presented. The analysis uses the experimentally determined values of the mixing angles in the lepton mixing matrix in order to explore the allowed values…

High Energy Physics - Phenomenology · Physics 2014-06-09 J. Alberto Acosta , Alfredo Aranda , Julio Virrueta

The phenomenology of 3-neutrino mixing, the current status of our knowledge about the 3-neutrino mixing parameters, including the absolute neutrino mass scale, and of the Dirac and Majorana CP violation in the lepton sector, are reviewed.…

High Energy Physics - Phenomenology · Physics 2014-05-12 S. T. Petcov

We consider a class of models of neutrino mixing with $S_4$ lepton flavour symmetry combined with a generalised CP symmetry, which are broken to residual $Z_2$ and $Z_2 \times H^\nu_{\rm CP}$ symmetries in the charged lepton and neutrino…

High Energy Physics - Phenomenology · Physics 2017-12-07 J. T. Penedo , S. T. Petcov , A. V. Titov

The neutrino mass matrix has remnant CP symmetry expressed in terms of the lepton mixing matrix, and vice versa the remnant CP transformations allow us to reconstruct the mixing matrix. We study the scenario that all the four remnant CP…

High Energy Physics - Phenomenology · Physics 2015-10-07 Peng Chen , Chang-Yuan Yao , Gui-Jun Ding

We analyse the interplay of generalised CP transformations and the non-Abelian discrete group $T^{\prime}$ and use the semi-direct product $G_f= T^{\prime}\rtimes H_{\text{CP}}$, as family symmetry acting in the lepton sector. The family…

High Energy Physics - Phenomenology · Physics 2014-05-20 Ivan Girardi , Aurora Meroni , S. T. Petcov , Martin Spinrath

Assuming a minimal seesaw model with two heavy neutrinos (N), we examine effects of leptonic CP violation induced by approximate mu-tau symmetric interactions. As long as N is subject to the mu-tau symmetry, we can choose CP phases of Dirac…

High Energy Physics - Phenomenology · Physics 2008-11-26 Teppei Baba , Masaki Yasue

From the new existing data with not vanishing theta13 mixing angle we determine the possible shape of the Majorana neutrino mass matrix. We assume that CP symmetry is broken and all Dirac and Majorana phases are taken into account. Two…

High Energy Physics - Phenomenology · Physics 2012-04-18 Bartosz Dziewit , Sebastian Zajac , Marek Zralek

We explore the connection between low-scale CP-violating Dirac phase~$(\delta)$ and high-scale leptogenesis in a Left-Right Symmetric Model (LRSM) with scalar bidoublet and doublets. The fermion sector of the model is extended with one…

High Energy Physics - Phenomenology · Physics 2024-03-11 Utkarsh Patel , Pratik Adarsh , Sudhanwa Patra , Purushottam Sahu