The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Yoshio Koide - One of the best experts on this subject based on the ideXlab platform.
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Neutrino Mass Matrix Model with Only Three Adjustable Parameters
arXiv: High Energy Physics - Phenomenology, 2019Co-Authors: Yoshio Koide, Hiroyuki NishiuraAbstract:Stimulated by a successful quark Mass Matrix model based on U(3)$\times$U(3)$'$ family symmetry, a phenomenological neutrino Mass Matrix for the Majorana neutrinos $(\nu_L, \nu_R^c, N_L, N_R^c)$ is proposed. The model has only three adjustable parameters. Nevertheless, the model gives reasonable predictions for the neutrino Masses, mixings, and CP violating phases in the neutrino mixing Matrix.
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Structure of right-handed neutrino Mass Matrix
Physical Review D, 2017Co-Authors: Yoshio KoideAbstract:Recently, Nishiura and the author proposed a unified quark-lepton Mass Matrix model under a family symmetry $\mathrm{U}(3)\ifmmode\times\else\texttimes\fi{}\mathrm{U}(3{)}^{\ensuremath{'}}$. The model can give excellent parameter fitting to the observed quark and neutrino data. The model has a reasonable basis as far as the quark sector, but, in the neutrino sector, the form of the right-handed neutrino Mass Matrix ${M}_{R}$ does not have a theoretical basis; that is, it was nothing but a phenomenological assumption. In this paper, it is pointed out that the form of ${M}_{R}$ is originated in the structure of Majorana Mass Matrix ($4\ifmmode\times\else\texttimes\fi{}4$ Matrix) for the left-handed fields $(({\ensuremath{\nu}}_{L}{)}_{i},({\ensuremath{\nu}}_{R}^{c}{)}^{i},({N}_{L}{)}_{\ensuremath{\alpha}},({N}_{R}^{c}{)}^{\ensuremath{\alpha}})$ where ${\ensuremath{\nu}}_{i}$ ($i=1$, 2, 3) and ${N}_{\ensuremath{\alpha}}$ ($\ensuremath{\alpha}=1$, 2, 3) are U(3)-family and ${\mathrm{U}(3)}^{\ensuremath{'}}$-family triplets, respectively.
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neutrino Mass Matrix model with a bilinear form
Journal of High Energy Physics, 2013Co-Authors: Yoshio Koide, Hiroyuki NishiuraAbstract:A neutrino Mass Matrix model with a bilinear form $ {M_{\nu }}={k_{\nu }}{{\left( {{M_D}M_R^{-1 }M_D^T} \right)}^2} $ is proposed within the framework of the so-called yukawaon model, which has been proposed for the purpose of a unified description of the lepton mixing Matrix U PMNS and the quark mixing Matrix V CKM. The model has only two adjustable parameters for the PMNS mixing and neutrino Mass ratios. (Other parameters are fixed from the observed quark and charged lepton Mass ratios and the CKM mixing.) The model gives reasonable values sin2 2θ 12 ≃ 0.85, sin2 2θ 23 ~ 1 and sin2 2θ 13 ~ 0.09 together with $ {R_{\nu }}\equiv {{{\varDelta m_{21}^2}} \left/ {{\varDelta m_{32}^2}} \right.}\sim 0.03 $ . Our prediction of the effective neutrino Mass 〈m〉 in the neutrinoless double beta decay takes a sizable value 〈m〉 ≃ 0.0034 eV.
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neutrino Mass Matrix model with a bilinear form
arXiv: High Energy Physics - Phenomenology, 2013Co-Authors: Yoshio Koide, Hiroyuki NishiuraAbstract:A neutrino Mass Matrix model with a bilinear form $M_\nu = k_\nu (M_D M_R^{-1} M_D^T)^2$ is proposed within the framework of the so-called yukawaon model, which has been proposed for the purpose of a unified description of the lepton mixing Matrix $U_{PMNS}$ and the quark mixing Matrix $V_{CKM}$. The model has only two adjustable parameters for the PMNS mixing and neutrino Mass atios. (Other parameters are fixed from the observed quark and charged lepton Mass ratios and the CKM mixing.) The model gives reasonable values $\sin^2 2\theta_{12} \simeq 0.85$ and $\sin^2 2\theta_{23} \sim 1$ and $\sin^2 2\theta_{13} \sim 0.09$ together with $R_\nu \equiv \Delta m^2_{21}/\Delta m^2_{32} \sim 0.03$. Our prediction of the effective neutrino Mass $ $ in the neutrinoless double beta decay takes a sizable value $ \simeq 0.0034$ eV.
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Quark Mass Matrix Model for Neutrino Mixing
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Yoshio KoideAbstract:For the purpose of deriving the observed nearly tribimaximal neutrino mixing, a possible quark Mass Matrix model is investigated based on a yukawaon model. The neutrino Mass Matrix is related to the up-quark Mass Matrix. Five observable quantities (2 up-quark Mass ratios and 3 neutrino mixing parameters) are excellently fitted by two parameters (one parameter in the up-quark Mass Matrix and another one in the neutrino Mass Matrix). Also, the CKM mixing parameters and down-quark Mass ratios are given under the other 2 parameters.
L. Lavoura - One of the best experts on this subject based on the ideXlab platform.
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A three-parameter neutrino Mass Matrix with maximal CP violation
Physics Letters B, 2009Co-Authors: Walter Grimus, L. LavouraAbstract:Using the seesaw mechanism, we construct a model for the light-neutrino Majorana Mass Matrix which yields trimaximal lepton mixing together with maximal CP violation and maximal atmospheric-neutrino mixing. We demonstrate that, in our model, the light-neutrino Mass Matrix retains its form under the one-loop renormalization-group evolution. With our neutrino Mass Matrix, the absolute neutrino Mass scale is a function of |U_e3| and of the atmospheric Mass-squared difference. We study the effective Mass in neutrinoless double beta-decay as a function of |U_e3|, showing that it contains a fourfold ambiguity.Comment: 15 pages, one figur
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A Three-parameter neutrino Mass Matrix with maximal CP violation
Physics Letters B, 2008Co-Authors: Walter Grimus, L. LavouraAbstract:Abstract Using the seesaw mechanism, we construct a model for the light-neutrino Majorana Mass Matrix which yields trimaximal lepton mixing together with maximal CP violation and maximal atmospheric-neutrino mixing. We demonstrate that, in our model, the light-neutrino Mass Matrix retains its form under the one-loop renormalization-group evolution. With our neutrino Mass Matrix, the absolute neutrino Mass scale is a function of | U e 3 | and of the atmospheric Mass-squared difference. We study the effective Mass in neutrinoless ββ decay as a function of | U e 3 | , showing that it contains a fourfold ambiguity.
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Zeros of the inverted neutrino Mass Matrix
Physics Letters B, 2005Co-Authors: L. LavouraAbstract:I investigate viable textures with two texture zeros for the inverted neutrino Mass Matrix, and present the predictions of those textures for the neutrino Masses and for lepton mixing. By using an Abelian symmetry and one or two heavy scalar singlets, I construct realizations of those textures in the context of seesaw models.
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Zeros of the inverted neutrino Mass Matrix
Physics Letters B, 2005Co-Authors: L. LavouraAbstract:I investigate viable textures with two texture zeros for the inverted neutrino Mass Matrix, and present the predictions of those textures for the neutrino Masses and for lepton mixing. By using an Abelian symmetry and one or two heavy scalar singlets, I construct realizations of those textures in the context of seesaw models.Comment: 7 pages, LaTe
Morimitsu Tanimoto - One of the best experts on this subject based on the ideXlab platform.
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Hybrid Textures of Neutrino Mass Matrix
arXiv: High Energy Physics - Phenomenology, 2005Co-Authors: Satoru Kaneko, H. Sawanaka, Morimitsu TanimotoAbstract:We present analyses of the sixty hybrid textures of neutrino Mass Matrix, which have an equality of Matrix elements and one zero. These textures are possibly derived in the models with discrete flavor symmetry. Only six textures among sixty ones are excluded by the present experimental data. Since there are many textures which give similar predictions, the textures are classified based on the numerical results. The neutrinoless double beta decay is also examined in these textures. Our results suggest that there remain still rich structures of the neutrino Mass Matrix in the phenomenological point of view.
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Neutrino Mass Matrix with Two Zeros and Leptogenesis
Physics Letters B, 2003Co-Authors: Satoru Kaneko, Morimitsu TanimotoAbstract:The leptogenesis is studied in the neutrino Mass Matrix with two zeros, which reduces the number of independent phases of the CP violation. These texture zeros are decomposed into the Dirac neutrino Mass Matrix and the right-handed Majorana one in the see-saw mechanism. It is found that there are six textures for the Dirac neutrino Mass Matrix, among which one texture with three zeros has three phases, three textures with four zeros have two phases, and two textures with five zeros have only one phase in the basis with the real right-handed Majorana Mass Matrix. The relation between the leptogenesis and the low energy CP violation is discussed in typical textures. It is remarked that the leptogenesis is linked strongly with the CP violation in the neutrino oscillations. The predicted baryon asymmetry of the universe is consistent with the observed value.
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Zee-type Neutrino Mass Matrix and Bi-Maximal Mixing
arXiv: High Energy Physics - Phenomenology, 2000Co-Authors: Masahisa Matsuda, Cecilia Jarlskog, Solveig Skadhauge, Morimitsu TanimotoAbstract:It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino Mass Matrix with three flavors to the current atmospheric and solar neutrino experimental data. The Mass of the lightest neutrino, which consist mostly of $\nu_{\mu}$ and $\nu_{\tau}$, is $\simeq \Delta m_{\odot}^2/(2\sqrt{\Delta m_{atm}^2})$. The related topics on Zee-type neutrino Mass Matrix are also discussed.
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Natural Neutrino Mass Matrix
Physical Review D, 1998Co-Authors: Masahisa Matsuda, Morimitsu TanimotoAbstract:The naturalness of the neutrino Mass hierarchy and mixing is studied. First we select a few patterns from among 12 neutrino mixing patterns, which could form the natural neutrino Mass Matrix. Further we show that if the Dirac neutrino Mass Matrix is taken as the natural one in the quark sector, then only two mixing patterns without large mixing lead to the natural right-handed Majorana Mass Matrix. The rest of the chosen patterns with three degenerate Mass solutions lead to the unnatural right-handed Majorana Mass Matrix in the seesaw mechanism. Notice, however, that for the chosen two natural patterns there could be a huge Mass hierarchy such as $\mathcal{O}{(10}^{4}--{10}^{6})$ in order to reproduce the inverse Mass hierarchy of the light neutrinos.
Radha Raman Gautam - One of the best experts on this subject based on the ideXlab platform.
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Zeros in the magic neutrino Mass Matrix
Physical Review D, 2016Co-Authors: Radha Raman Gautam, Sanjeev KumarAbstract:We study the phenomenology of the magic neutrino Mass Matrix with two texture zeros. In the diagonal charged lepton basis, seven patterns with two texture zeros in the neutrino Mass Matrix (\(M_\nu \)) are consistent with the neutrino oscillation data. When we consider the coexistence of magic symmetry and two texture zeros in \(M_\nu \), we find that only two patterns of two texture zeros namely: \(A_1\) and \(A_2\) remain compatible with the recent neutrino oscillation data. For the allowed patterns we express the neutrino Masses and mixing angles in terms of one unknown phase \(\phi \) and two known parameters: \(\varDelta m^{2}_{21}\) and \(r=\varDelta m^{2}_{21}/\varDelta m^{2}_{23}\). In particular, we find \(\sin ^2 \theta _{13}=(2/3)r/(1+r)\) is predicted for both patterns. We also show the possibility of realizing these patterns using discrete non-Abelian symmetry group \(A_4\).
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Hybrid Textures of the Right-Handed Majorana Neutrino Mass Matrix
Physical Review D, 2013Co-Authors: S. Dev, Radha Raman Gautam, Lal SinghAbstract:We perform a systematic study of neutrino Mass matrices having a vanishing cofactor and an equality between two cofactors of the Mass Matrix. Such texture structures of the effective neutrino Mass Matrix arise from type-I seesaw mechanism when the Dirac neutrino Mass Matrix is diagonal with equal elements and the right-handed Majorana neutrino Mass Matrix has hybrid textures with one equality of Matrix elements and one zero Matrix element. For three right-handed neutrinos there are sixty possible hybrid textures out of which only six are excluded by the present experimental data. We show that such textures can be derived using discrete symmetries. The predictions of experimentally allowed textures are examined for unknown parameters such as the effective Majorana Mass of the electron neutrino and the Dirac-type CP-violating phase.
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Broken S 3 Symmetry in the Neutrino Mass Matrix
Physics Letters B, 2011Co-Authors: S. Dev, Shivani Gupta, Radha Raman GautamAbstract:We explore the feasibility of the discrete flavor symmetry S3 to explain the pattern of neutrino Masses and mixings. In the flavor basis, the neutrino Mass Matrix is taken to be invariant under S3 symmetry at the zeroth order. The effects of breaking S3 symmetry by matrices invariant under different S2 subgroups of S3 are studied. The resulting retrocirculant perturbation Matrix leads to the perturbed S3 neutrino Mass Matrix having a trimaximal eigenvector as suggested by the solar neutrino data. It is found that after the third order perturbation the neutrino mixings only depend on the perturbation parameter and are consistent with the current experimental data leading to very small deviations from tribimaximal mixing. These perturbations in the S3 invariant neutrino Mass Matrix result in interesting interplay between the solar and the reactor neutrino mixing angles. We also get a strongly suppressed range of effective Majorana Mass which lies well within the reach of the ongoing experiments.
Alexei Yu. Smirnov - One of the best experts on this subject based on the ideXlab platform.
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Neutrino Mass Matrix : inverted hierarchy and CP violation
Physical Review D, 2003Co-Authors: Michele Frigerio, Alexei Yu. SmirnovAbstract:We reconstruct the neutrino Mass Matrix in flavor basis, in the case of inverted Mass hierarchy (ordering), using all available experimental data on neutrino Masses and oscillations. We analyze the dependence of the Matrix elements m_{alpha beta} on the CP violating Dirac, delta, and Majorana, rho and sigma, phases, for different values of the absolute Mass scale. We find that the present data admit various structures of the Mass Matrix: (i) hierarchical structures with a set of small (zero) elements; (ii) structures with equalities among various groups of elements: e-row and/or mu tau-block elements, diagonal and/or off-diagonal elements; (iii) ``democratic'' structure. We find values of phases for which these structures are realized. The Mass Matrix elements can anti-correlate with flavor: inverted partial or complete flavor alignment is possible. For various structures of the Mass Matrix we identify possible underlying symmetry. We find that the Mass Matrix can be reconstructed completely only in particular cases, provided that the absolute scale of the Mass is measured. Generally, the freedom related to the Majorana phase sigma will not be removed, thus admitting various types of Mass Matrix.
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Structure of neutrino Mass Matrix and CP violation
Nuclear Physics B, 2002Co-Authors: Michele Frigerio, Alexei Yu. SmirnovAbstract:We reconstruct the neutrino Mass Matrix in the flavor basis, using all available experimental data on neutrino oscillations. Majorana nature of neutrinos, normal Mass hierarchy (ordering) and validity of the LMA MSW solution of the solar neutrino problem are assumed. We study dependences of the Mass Matrix elements, m_{alpha beta}, on the CP violating Dirac, delta, and Majorana, rho, sigma, phases, for different values of the mixing angle theta_{13} and of the absolute Mass scale, m_1. The contours of constant Mass in the rho-sigma plane have been constructed for all m_{alpha beta}. These rho-sigma plots allow to systematically scan all possible structures of the Mass Matrix. We identify regions of parameters in which the Matrix has (i) a structure with the dominant mu tau-block, (ii) various hierarchical structures, (iii) flavor alignment, (iv) structures with special ordering or equalities of elements, (v) the democratic form. In certain cases the Matrix can be parameterized by powers of a unique expansion (ordering) parameter lambda approximately 0.2 - 0.3 (lambda_{ord} approximately 0.6 - 0.7). Perspectives to further restrict the structure of Mass Matrix in future experiments, in particular in the beta beta_{0 nu}-decay searches, are discussed.
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Neutrinos with Zee-Mass Matrix in Vacuum and Matter
Nuclear Physics B, 1994Co-Authors: Alexei Yu. Smirnov, Zhijian TaoAbstract:Neutrino Mass Matrix generated by the Zee (radiative) mechanism has zero (in general, small) diagonal elements and a natural hierarchy of the nondiagonal elements. It can be considered as an alternative (with strong predictive power) to the matrices generated by the see-saw mechanism. The propagation in medium of the neutrinos with the Zee-Mass Matrix is studied. The flavor neutrino transitions are described analytically. In the physically interesting cases the probabilities of transitions as functions of neutrino energy can be represented as two-neutrino probabilities modulated by the effect of vacuum oscillations related to the small Mass splitting. Possible applications of the results to the solar, supernova, atmospheric and relic neutrinos are discussed. A set of the predictions is found which could allow to identify the Zee-Mass Matrix and therefore the corresponding mechanism of Mass generation.
