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Related papers: U_{PMNS} = U_ell^dagger U_nu

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We note that a simple two parameter description of lepton mixing is possible which reproduces the features that apparently emerge from global fits at the 1\sigma level: if U_{e3} is non-zero it implies that the solar neutrino mixing…

High Energy Physics - Phenomenology · Physics 2015-06-05 Werner Rodejohann , He Zhang

There are three observables related to neutrino mass, namely the kinematic mass in direct searches, the effective mass in neutrino-less double beta decay, and the sum of neutrino masses in cosmology. In the limit of exactly degenerate…

High Energy Physics - Phenomenology · Physics 2010-05-12 Werner Rodejohann

In drawing on an analogy with the flavor mixing observed in the quark sector we discuss a pattern of large flavor mixing angles in the lepton sector. Simple arguments based on a democratic symmetry and its violation in the lepton sector…

High Energy Physics - Phenomenology · Physics 2007-05-23 Harald Fritzsch , Zhi-Zhong Xing

On account of the new neutrino oscillation data signalling a non-zero value for the smallest mixing angle ($\theta_z$), we present an explicit realization of the underlying U(1) symmetry characterizing the maximal atmospheric mixing angle…

High Energy Physics - Phenomenology · Physics 2013-05-30 E. I. Lashin , N. Chamoun , S. Nasri

Neutrino oscillations reveal several small parameters, namely, $\theta_{13}$, the solar mass splitting {\em vis-\`{a}-vis} the atmospheric one, and the deviation of $\theta_{23}$ from maximal mixing. Can these small quantities all be traced…

High Energy Physics - Phenomenology · Physics 2015-05-27 Soumita Pramanick , Amitava Raychaudhuri

It is shown that empirical relations between the charged lepton spectra and the quark spectra together with a bimaximal or near bimaximal neutrino mixing matrix necessarily imply that there is a contribution to U(e3) given by…

High Energy Physics - Phenomenology · Physics 2009-11-10 Javier Ferrandis , Sandip Pakvasa

Atmospheric neutrinos at low energies, $E \lsim 500$ MeV, is known to be a rich source of information of lepton mixing parameters. We formulate a simple perturbative framework to elucidate the characteristic features of neutrino oscillation…

High Energy Physics - Phenomenology · Physics 2019-12-06 Ivan Martinez-Soler , Hisakazu Minakata

The recent results from T2K and MINOS experiments point towards a relatively large value of the reactor angle \theta_13 in the lepton sector. In this paper we show how a large \theta_13 can arise from the charged lepton sector alone in the…

High Energy Physics - Phenomenology · Physics 2011-11-22 David Marzocca , Serguey T. Petcov , Andrea Romanino , Martin Spinrath

With one \Delta m^2 of the appropriate order of magnitude to solve the atmospheric neutrino problem, we study the resulting three-generation vacuum-oscillation fit to the solar neutrino flux. An explanation of the atmospheric neutrino…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Osland , G. Vigdel

In the present work, the inverted hierarchical neutrino mass model which is characterised by opposite CP parity in the first two mass eigenvalues $(m_1,-m_2,m_3)$, is studied in order to lower the predicted value of solar mixing angle…

High Energy Physics - Phenomenology · Physics 2008-11-26 N. Nimai Singh , Monisa Rajkhowa , Abhijit Borah

We propose a parametrization of the lepton mixing matrix in terms of an expansion in powers of the deviations of the reactor, solar and atmospheric mixing angles from their tri-bimaximal values. We show that unitarity triangles and neutrino…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. F. King

The 3-3-1 model proposed in 2011 based on discrete symmetry $S_4$ responsible for the neutrino and quark masses is updated, in which the non-zero $\theta_{13}$ is focused. Neutrino masses and mixings are consistent with the most recent data…

High Energy Physics - Phenomenology · Physics 2015-06-22 Vo Van Vien , Hoang Ngoc Long , Dinh Phan Khoi

We study the case of $U^T_l$ presenting the exact bi-maximal mixing form with $U_\nu$ inducing the deviation from the bi-maximal mixing in the final form of the Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing, $U_{PMNS}=U^T_l U_\nu$. We…

High Energy Physics - Phenomenology · Physics 2009-11-10 C. A. de S. Pires

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

Many experiments are being planned to measure the neutrino mixing parameter $\theta_{13}$ using reactor as well as accelerator neutrino beams. In this note, the theoretical significance of a high precision measurement of this parameter is…

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

We have discussed predictions of $|U_{e3}|$ and $J_{CP}$ in the framework of the neutrino mass matrix with two zeros. In the case of the best fit values of $\tan^2\theta_{12}$, $\tan^2\theta_{23}$, $\Delta m^2_{\rm sun}$ and $\Delta m_{\rm…

High Energy Physics - Phenomenology · Physics 2009-11-10 Mizue Honda , Satoru Kaneko , Morimitsu Tanimoto

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

In this paper, we derive in a novel approach the possible textures of neutrino mass matrix that can lead to maximal atmospherical mixing angle ($\theta^{}_{23} = \pi/4$) and Dirac CP phase ($\delta = - \pi/2$) in two phenomenologically…

High Energy Physics - Phenomenology · Physics 2019-05-08 Zhi-Cheng Liu , Chong-Xing Yue , Zhen-hua Zhao

In the present work we have investigated some patterns of broken ``scaling" ansatz of the neutrino mass matrix. The scaling neutrino mass matrix is disallowed by the current neutrino oscillation data as, among others, it predicts vanishing…

High Energy Physics - Phenomenology · Physics 2025-03-12 Ajay Kumar , Dikshit Gautam , Surender Verma

In this paper, we consider a neutrino mass model based on $A_4$ symmetry. The spontaneous symmetry breaking in this model is chosen to obtain tribimaximal mixing in the neutrino sector. We introduce $Z_2 \times Z_2$ invariant perturbations…

High Energy Physics - Phenomenology · Physics 2022-09-07 Abhish Dev , P. Ramadevi , S. Uma Sankar