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We propose a new D4 flavor model based on SU(3)C⊗SU(3)L⊗U(1)'X gauge symmetry responsible for fermion masses and mixings in which all fermion fields act only as singlets under D4 which differs from our previous work. The neutrinos get small masses from two SU(3)L, anti-sextets and one SU(3)L, triplet which are all in singlets under D4. If a SU(3)L Higgs triplet, lying in 1''' under D4, is considered as a perturbation the corresponding neutrino mass mixing matrix gets the most general form. In this case, the model can fit the most recent data on neutrino masses and mixing with nonzero θ13. Our results show that the neutrino masses are naturally small. The sum of three light neutrino masses and the effective mass governing neutrinoless double beta decay are obtained that are consistent with the recent data. [ABSTRACT FROM AUTHOR]

The exact solution for the neutrino mass matrix of the Zee-Babu model is derived. Tribimaximal mixing imposes conditions on the Yukawa couplings, from which the normal mass hierarchy is preferred. The derived conditions give a possibility of Majorana maximal CP violation in the neutrino sector. We have shown that nonzero θ13 is generated if Yukawa couplings between leptons almost equal to each other. The model gives some regions of the parameters where neutrino mixing angles and the normal neutrino mass hierarchy obtained are consistent with the recent experimental data. [ABSTRACT FROM AUTHOR]

We have described the quark and lepton masses and mixings in context of non-SUSY SO(IO) and "four-zero-texture" (FZT). In the FZT case, the fermion masses and the mixing angles can be related. We predict the neutrino masses using the near tribimaximal (TBM) mixing and the triminimal mixing. Our results show that under TBM, the neutrinos have a normal, but weak hierarchy. Variations of the neutrino masses under the "Near TBM-scenario" are also discussed. [ABSTRACT FROM AUTHOR]

We consider two Ansatze for the neutrino masses and mixings in which the permutation symmetry is implemented in various orders. We discuss the possible seesaw mechanisms and the charged lepton masses for the two cases in the presence of a Higgs triplet and three Higgs doublets. [ABSTRACT FROM AUTHOR]

We investigate the comparative studies of cosmological baryon asymmetry in different neutrino mass models with and without θ13 by considering the three-diagonal form of Dirac neutrino mass matrices and the three aspects of leptogenesis, unflavoured, flavoured, and nonthermal.We found that the estimations of anymodels with θ13 are consistent in all the three stages of calculations of leptogenesis and the results are better than the predictions of any models without θ13 which are consistent in a piecemealmanner with the observational data in all the three stages of leptogenesis calculations. For the normal hierarchy of Type-IA with charged lepton matrix, model with and without θ13 predicts inflaton mass required to produce the observed baryon asymmetry to be Mϕ ~ 2.2 × 1011 GeV andMϕ ~ 3.6 × 1010 GeV, and the corresponding reheating temperatures are TR ~ 4.86 × 106 GeV and TR ~ 4.50 × 106 GeV respectively. These predictions are not in conflict with the gravitino problem which required the reheating temperature to be below 107 GeV. And these values apply to the recent discovery of Higgs boson of mass ~125GeV. [ABSTRACT FROM AUTHOR]

Assuming that the leptonic mixing matrix is given in first approximation by the tribimaximal form or a generalization of this, we deduce some consequences with regard to the finite symmetries that may be applied in the minimal lepton sector of the electroweak theory. [ABSTRACT FROM AUTHOR]

We construct a D4 flavor model based on SU(3)C ⊗SU(3)L ⊗U(1)X gauge symmetry responsible for fermion masses and mixings. The neutrinos get small masses from antisextets which are in a singlet and a doublet under D4. If the D4 symmetry is violated as perturbation by a Higgs triplet under SU(3)L and lying in of D4, the corresponding neutrino mass mixing matrix gets the most general form. In this case, the model can fit the experimental data in 2012 on neutrino masses and mixing. Our results show that the neutrino masses are naturally small and a little deviation from the tribimaximal neutrino mixing form can be realized. The quark masses and mixing matrix are also discussed. In the model under consideration, the CKM matrix can be different from the unit matrix. The scalar potential of the model is more simpler than those of the model based on S3 and S4. Assignation of VEVs to antisextets leads to the mixing of the new gauge bosons and those in the Standard Model. The mixing in the charged gauge bosons as well as the neutral gauge boson is considered. [ABSTRACT FROM AUTHOR]

We obtain analytical formulas which connect the neutrino masses and the leptonic mixing matrix with the entries in the mass matrix for the approximation in which the charged lepton mixing matrix is the unit matrix. We also extract the CP violation phase and determine the conditions in which this is present. [ABSTRACT FROM AUTHOR]

A brief discussion about the current status of the search for the possible finite symmetry of a leptonic mass matrix is presented. Possible extensions of the models of leptons that can describe the masses and mixing elements are discussed. [ABSTRACT FROM AUTHOR]

We analyse the mass matrix of the three light neutrinos in the basis where the charged-lepton mass matrix is diagonal and discuss constraints on its elements for the Majorana and the Dirac case. [ABSTRACT FROM AUTHOR]

It has been suggested that residual symmetries in the charged-lepton and neutrino mass matrices can possibly reveal the flavour symmetry group of the lepton sector. We review the basic ideas of this purely grouptheoretical approach and discuss some of its results. Finally, we also list its shortcomings. [ABSTRACT FROM AUTHOR]

The recent results from Daya Bay and RENO reactor neutrino experiments have firmly established that the smallest reactor mixing angle θ13 is nonvanishing at the 5 σ level, with a relatively large value, i.e. θ13 ≈ 9°. Using the fact that the neutrino mixing matrix can be represented as , where Ul and Uν result from the diagonalization of the charged lepton and neutrino mass matrices and Pν is a diagonal matrix containing the Majorana phases and assuming the tri-bimaximal (TBM) form for Uν, we investigate the possibility of accounting for the large reactor mixing angle due to the corrections of the charged lepton mixing matrix. The form of Ul is assumed to be that of CKM mixing matrix of the quark sector. We find that with this modification it is possible to accommodate the large observed reactor mixing angle θ13. We also study the implications of such corrections on the other phenomenological observables. [ABSTRACT FROM AUTHOR]

Within the type-I seesaw and in the basis where charged lepton and heavy neutrino mass matrices are real and diagonal, μΤ symmetric four and three zero neutrino Yukawa textures are perturbed by lowest order μΤ symmetry breaking terms. These perturba-tions are taken to be the most general ones for those textures. For quite small values of those symmetry breaking parameters, permitting a lowest order analysis, current best-fit ranges of neutrino mass squared differences and mixing angles are shown to be accom-modable, including a value of θ13 in the observed range, provided all the light neutrinos have an inverted mass ordering. [ABSTRACT FROM AUTHOR]

The lepton-charge ( L, L, L) nonconserving interaction leads to the mixing of the electron, muon, and tau neutrinos, which manifests itself in spatial oscillations of a neutrino beam, and also to the mixing of the electron, negative muon, and tau lepton, which, in particular, may be the cause of the 'forbidden' radiative decay of the negative muon into the electron and γ quantum. Under the assumption that the nondiagonal elements of the mass matrices for neutrinos and ordinary leptons, connected with the lepton charge nonconservation, are the same, and by performing the joint analysis of the experimental data on neutrino oscillations and experimental restriction for the probability of the decay µ → e + γ per unit time, the following estimate for the lower bound of neutrino mass has been obtained: m > 1.5 eV/ c. [ABSTRACT FROM AUTHOR]

We investigate the possibility that the first column of the lepton mixing matrix U is given by u1 = (2, - 1, - 1)T / √6. In a purely group-theoretical approach, based on residual symmetries in the charged-lepton and neutrino sectors and on a theorem on vanishing sums of roots of unity, we discuss the finite groups which can enforce this. Assuming that there is only one residual symmetry in the Majorana neutrino mass matrix, we find the almost unique solution ℤq x S4 where the cyclic factor ℤq with q = 1, 2, 3, ... is irrelevant for obtaining u1 in U. Our discussion also provides a natural mechanism for achieving this goal. Finally, barring vacuum alignment, we realize this mechanism in a class of renormalizable models. [ABSTRACT FROM AUTHOR]

We review the renormalization group evolution of quark and lepton masses, mixing angles and phases both in the UED extension of the Standard Model (SM) and of the Minimal Supersymmetric Standard Model (MSSM). We consider two typical scenarios: all matter fields propagating in the bulk and matter fields constrained to the brane. The resulting renormalization group evolution equations in these scenarios are compared with the existing results in the literature, together with their implications. [ABSTRACT FROM AUTHOR]

We describe the effects of neutrino propagation in the matter of the Earth relevant to experiments with atmospheric and accelerator neutrinos and aimed at the determination of the neutrino mass hierarchy and CP violation. These include (i) the resonance enhancement of neutrino oscillations in matter with constant or nearly constant density, (ii) adiabatic conversion in matter with slowly changing density, (iii) parametric enhancement of oscillations in a multilayer medium, and (iv) oscillations in thin layers of matter. We present the results of semianalytic descriptions of flavor transitions for the cases of small density perturbations, in the limit of large densities and for small density widths. Neutrino oscillograms of the Earth and their structure after determination of the 1-3 mixing are described. A possibility to identify the neutrino mass hierarchy with the atmospheric neutrinos and multimegaton scale detectors having low energy thresholds is explored. The potential of future accelerator experiments to establish the hierarchy is outlined. [ABSTRACT FROM AUTHOR]

We present a revised version of the so-called 'yukawaon model', which was proposed for the purpose of a unified description of the lepton mixing matrix U and the quark mixing matrix V. It is assumed from a phenomenological point of view that the neutrino Dirac mass matrix M is given with a somewhat different structure from the charged lepton mass matrix M, although M= M was assumed in the previous model. As a result, the revised model predicts a reasonable value sin2 θ∼0.07 with keeping successful results for other parameters in U as well as V and quark and lepton mass ratios. [ABSTRACT FROM AUTHOR]

Abstract: We review the status and future of ongoing searches for neutrino-less double beta decay, a lepton-number violating nuclear decay whose existence would imply that neutrinos are their own antiparticles, i.e Majorana particles. The measurement of its decay rate is arguably the most sensitive laboratory probe of the absolute mass of neutrinos. Emphasis is given to the most promising detector technologies in the field which aim at exploring the inverted hierarchy region of neutrino masses. [Copyright &y& Elsevier]

We review the main features and results of thermal leptogenesis within the type I seesaw mechanism, the minimal extension of the Standard Model explaining neutrino masses and mixing. After presenting the simplest approach, the vanilla scenario, we discuss various important developments of recent years, such as the inclusion of lepton and heavy neutrino flavour effects, a description beyond a hierarchical heavy neutrino mass spectrum and an improved kinetic description within the density matrix and the closed-timepath formalisms. We also discuss how leptogenesis can ultimately represent an important phenomenological tool to test the seesaw mechanism and the underlying model of new physics. [ABSTRACT FROM AUTHOR]

We present an overview on some basic properties of massive neutrinos and focus on their flavor issues, including the mass spectrum, flavor mixing pattern and CP violation. The lepton flavor structures are explored by taking into account of the observed value of the smallest neutrino mixing angle θ13. The impact of θ13 on the running behaviors of other flavor mixing parameters is discussed in some detail. The seesaw-induced enhancement of the electromagnetic dipole moments for three Majorana neutrinos is also discussed in a TeV seesaw scenario. [ABSTRACT FROM AUTHOR]

The status of neutrino oscillations from global data are summarized. An update on the three-flavour picture and recent developments are discussed with regard to the measurement of the mixing angle θ. Global data currently provide an indication at 3 σ that θ is non-zero. Furthermore, the status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of MiniBooNE results and a recent re-evaluation of the neutrino fluxes from nuclear reactors are discussed. Despite several hints for sterile neutrinos at the eV scale, there is severe tension in the global data and no consistent description of all data is possible. [ABSTRACT FROM AUTHOR]

The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. [ABSTRACT FROM AUTHOR]

We consider lepton flavour violation (LFV) in the charged lepton sector both from the bottom-up effective Lagrangian approach and from the top-down approach via various case studies that have been analysed. The implications for LFV studies at the LHC is briefly discussed. Finally the nature of LFV in the neutrino sector is considered, paying particular regard to the implications of the recent measurements of θ. [ABSTRACT FROM AUTHOR]

Lepton mass hierarchies and lepton flavour violation are revisited in the framework of Randall-Sundrum models. Models with Dirac-type as well as Majorana-type neutrinos are considered. The five-dimensional c-parameters are fit to the charged lepton and neutrino masses and mixings using χ minimization. Leptonic flavour violation is shown to be large in these cases. Schemes of minimal flavour violation are considered for the cases of an effective LLHH operator and Dirac neutrinos and are shown to significantly reduce the limits from lepton flavour violation. [ABSTRACT FROM AUTHOR]

We review observational evidence for a matter-antimatter asymmetry in the early universe, which leads to the remnant matter density we observe today. We also discuss bounds on the presence of antimatter in the present-day universe, including the possibility of a large lepton asymmetry in the cosmic neutrino background. We briefly review the theoretical framework within which baryogenesis, the dynamical generation of a matter-antimatter asymmetry, can occur. As an example, we discuss a testable minimal particle physics model that simultaneously explains the baryon asymmetry of the universe, neutrino oscillations and dark matter. [ABSTRACT FROM AUTHOR]

We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos. [ABSTRACT FROM AUTHOR]

We analyze neutrino masses and Lepton Flavor Violation (LFV) in charged leptons with a minimal ansatz about the breaking of the U(3) flavor symmetry, consistent with the U(2) breaking pattern of quark Yukawa couplings, in the context of supersymmetry. Neutrino masses are expected to be almost degenerate, close to present bounds from cosmology and 0 νββ experiments. We also predict s≈ s| V|/| V|≈0.16, in perfect agreement with the recent Daya-Bay result. For slepton masses below 1 TeV, barring accidental cancellations, we expect $\mathcal{B}(\mu\to e \gamma) > 10^{-13}$ and $\mathcal {B}(\tau\to\mu\gamma) > 10^{-9}$, within the reach of future experimental searches. [ABSTRACT FROM AUTHOR]

This is an introductory review of the main features of leptogenesis, one of the most attractive models of baryogenesis for the explanation of the matter–antimatter asymmetry of the Universe. The calculation of the asymmetry in leptogenesis is intimately related to neutrino properties so that leptogenesis is also an important phenomenological tool to test the see-saw mechanism for the generation of neutrino masses and mixing and the underlying theory beyond the Standard Model. [ABSTRACT FROM AUTHOR]

We discuss the neutrino oscillations, using texture zero mass matrices for the leptons, including radiative correction. The neutrino mixing angle θ13 is calculated and agrees with the result of the new Daya Bay experiment. [ABSTRACT FROM AUTHOR]

Even tiny lepton flavor violation (LFV) due to some New Physics is able to alter the conditions inside a collapsing supernova core and probably to facilitate the explosion. LFV emerges naturally in a see-saw type-II model of neutrino mass generation. Experimentally, the LFV beyond the Standard Model is constrained by rare lepton decay searches. In particular, strong bounds are imposed on the μ → eee branching ratio and on the μ- e conversion in muonic gold. Currently, the μ→ eγ is under investigation in the MEG experiment that aims at a dramatic increase in sensitivity in the next three years. We seek a see-saw type-II LFV pattern that fits all the experimental constraints, leads to Br(μ → eγ) ≳ Br(μμ → eee), and ensures a rate of LFV processes in supernova high enough to modify the supernova physics. These requirements are sufficient to eliminate almost all freedom in the model. In particular, they lead to the prediction 0.4 × 10 ≲ Br(μ → eγ) ≲ 6 × 10, which will be testable by MEG in the nearest future. The considered scenario also constrains the neutrino mass-mixing pattern and provides lower and upper bounds on τ-lepton LFV decays. We also briefly discuss a model with a single bilepton in which the μ → eee decay is absent at the tree level. [ABSTRACT FROM AUTHOR]

Some neutrino physics aspects of neutrino-less double beta decay are discussed: this includes the possibility to test or rule out the inverted neutrino mass ordering, distinguishing neutrino mass models, or the effects of light sterile neutrinos. [ABSTRACT FROM AUTHOR]

Neutrino-less double beta decays (0 νβ β) are sensitive and realistic probes for studying the Majorana nature of neutrinos, the ν mass spectrum and the absolute mass scale, the lepton sector CP and others beyond the standard electro-weak theory. This report reviews briefly 0 νβ β processes and Majorana neutrinos, the present and future 0 νβ β experiments and 0 νβ β nuclear matrix elements. [ABSTRACT FROM AUTHOR]

Texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings. In the present work, we have given an overview of all possible cases of Fritzsch-like as well as non-Fritzsch-like texture 6 and 5 zero fermion mass matrices. Further, for the case of texture 4 zero Fritzsch-like quark mass matrices, the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed. Furthermore, the case of texture 4 zero Fritzsch-like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both Majorana and Dirac neutrinos. [ABSTRACT FROM AUTHOR]

By introducing threeHiggs fields that are SU(2) doublets and a flavor permutational symmetry, S, in the theory, we extend the concepts of flavor and generations to the Higgs sector and formulate a Minimal S-Invariant Extension of the Standard Model. The mass matrices of the neutrinos and charged leptons are re-parameterized in terms of their eigenvalues, then the neutrino mixing matrix, V, is computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained in excellent agreement with the latest experimental data. We also compute the branching ratios of some selected flavor-changing neutral current (FCNC) processes, as well as the contribution of the exchange of neutral flavor-changing scalars to the anomaly of the magnetic moment of the muon, as functions of the masses of charged leptons and the neutral Higgs bosons. We find that the S × Z flavor symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector, well below the present experimental bounds by many orders of magnitude. The contribution of FCNC's to the anomaly of the muon's magnetic moment is small, but not negligible. [ABSTRACT FROM AUTHOR]

With the start of the LHC, interest in electroweak scale models for the neutrino mass has grown. In this paper, we review two specific models that simultaneously explain neutrino masses and provide a suitable DM candidate. We discuss the implications of these models for various observations and experiments including the LHC, Lepton Flavor Violating (LFV) rare decays, direct and indirect dark matter searches and kaon decay. [ABSTRACT FROM AUTHOR]

I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of left-right symmetric theories, which led originally to neutrino mass and the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. Moreover, LHC can measure the masses of the right-handed neutrinos and the right-handed leptonic mixing matrix, which could in turn be used to predict the rates for neutrinoless double decay and lepton flavor violating violating processes. The LR scale at the LHC energies offers great hope of observing these low energy processes in the present and upcoming experiments. [ABSTRACT FROM AUTHOR]

Consequences of the hypothesis that the Sp( pn/2) symplectic group is a broken gauge group of ( n) lepton flavors are considered. An invariant Majorana mass is impossible in Sp( pn/2). A dynamical spontaneous breaking of Sp( pn/2) is admissible only if the number of flavors is n = 6and if, simultaneously, parity ( R,L symmetry) violation occurs. The action of the seesaw mechanism generates here three light and three heavy Dirac neutrinos. The disregard of heavy particles in an R,L-symmetric system of weak and electromagnetic interactions ( R + L vector currents) leads to a theory featuring parity nonconservation and axial anomalies. Only a weak left-handed ( L) and a total ( R + L) electromagnetic current do not have anomalies and remain independent of high-mass physics. These are precisely Standard Model currents. [ABSTRACT FROM AUTHOR]

Radiative neutrino mass models have interesting features, which make it possible to relate neutrino masses to the existence of dark matter. However, the explanation of the baryon number asymmetry in the universe seems to be generally difficult as long as we suppose leptogenesis based on the decay of thermal right-handed neutrinos. Since right-handed neutrinos are assumed to have masses of O(1) TeV in these models, they are too small to generate the sufficient lepton number asymmetry. Here we consider Affleck-Dine leptogenesis in a radiative neutrino mass model by using a famous flat direction LHu as an alternative possibility. The constraint on the reheating temperature could be weaker than the ordinary models. The model explains all the origin of the neutrino masses, the dark matter, and also the baryon number asymmetry in the universe. [ABSTRACT FROM AUTHOR]

We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with μτ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors on the right-handed Majorana mass matrix having μτ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with μτ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass Mee, the absolute mass scale and the Majorana-type CP violating phases. [ABSTRACT FROM AUTHOR]