Zero minors of the neutrino mass matrix

We examine the possibility that a certain class of neutrino mass matrices, namely those with two independent vanishing minors in the flavor basis, regardless of being invertible or not, is sufficient to describe current data. We compute generic formulae for the ratios of the neutrino masses and for the Majorana phases. We find that seven textures with two vanishing minors can accommodate the experimental data. We present an estimate of the mass matrix for these patterns. All the possible textures can be dynamically generated through the seesaw mechanism augmented with a discrete Abelian symmetry.Comment: latex, 22 pages, 7 figures, 2 tables, accepted version to appear in PR

One vanishing minor in the neutrino mass matrix

We study a specific texture of the neutrino mass matrix, namely the models with one $2\times 2$ subdeterminant equal to zero. We carry out a complete phenomenological analysis with all possible relevant correlations. Every pattern of the six possible ones is found able to accommodate the experimental data, with three cases allowing also for non-invertible mass matrices. We present symmetry realizations for all the models.Comment: 21 pages, 11 figures, 4 table

Neutrino Mixing and Leptogenesis in μ−τ\mu-\tau Symmetry

We study the consequences of the $Z_2$-symmetry behind the $\mu$--$\tau$ universality in neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass hierarchies and generate enough lepton asymmetry to interpret the observed baryon asymmetry in the universe. We also show how a specific form of a high-scale perturbation is kept when translated via the seesaw into the low scale domain, where it can accommodate the neutrino mixing data. We finally present a realization of the high scale perturbed texture through addition of matter and extra exact symmetries.Comment: 29 pages, 1 figure, 3 tables. Complete re-analysis. Version to appear in PR

Form Invariance and Symmetry in the Neutrino Mass Matrix

We present the general form of the unitary matrices keeping invariant the Majorana neutrino mass matrix of specific texture suitable for explaining oscillation data. In the case of the Tri-bimaximal pattern with two degenerate masses we give a specific realization of the underlying $U(1)$ symmetry which can be uplifted to a symmetry in a complete theory including charged leptons. For this, we present a model with three light SM-like Higgs doublets and one heavy Higgs triplet and find that one can accommodate the hierarchy of the charged lepton masses. The lepton mass spectrum can also be achieved in another model extending the SM with three SM-singlet scalars transforming non trivially under the flavor symmetry. We discuss how such a model has room for generating enough baryon asymmetry through leptogenesis in the framework of Type-I and II seesaw mechanisms.Comment: 16 page

Textures of Neutrino Mass Matrix from S4S_4-flavor Symmetry

We study a texture of neutrino mass matrix characterized by two constraints consisting of one equality and another antiequality between two elements corresponding to two pairs of the matrix entries. Amidst such textures, we limit our study to three patterns which were realizable assuming an $S_4$-symmetry within type II-seesaw scenario. Three such cases were found and studied: I ($M_{\nu 22}=-M_{\nu 33}$ \& $M_{\nu 11}=+M_{\nu 23}$), II ($M_{\nu 11}=-M_{\nu 33}$ \& $M_{\nu 22}=+M_{\nu 13}$) and III ($M_{\nu 11}=-M_{\nu 22}$ \& $M_{\nu 33}=+M_{\nu 12}$). We specify the role of non-physical phases in the definition of the textures under study which were tested against experimental constraints, and were found to accommodate data with both hierarchies allowed. However, switching off the non-physical phases allows only for inverted hierarchy, except for the texture III which allows also, albeit for a very narrow parameter space region, for normal ordering. We present a complete phenomenological analysis of these three textures and justify analytically the resulting correlations. We detail the effect of the non-physical phases is diluting/deforming several correlations, which otherwise would have been ``clear". Finally, we give theoretical realizations within seesaw type II scenarios for such textures.Comment: 40 pages, pdflatex, 6 tables and 12 figures. arXiv admin note: text overlap with arXiv:2208.1034

The U(1) symmetry of the non-tribimaximal pattern in the degenerate mass spectrum case of the neutrino mass matrix

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 ($\theta_y = \pi / 4$) pattern with two degenerate masses but now with generic values of $\theta_z$. We study the effects of the form invariance with respect to U(1), and/or $Z_3$, $Z_2$ subgroups, on the Yukawa couplings and the mass terms. Later on, we specify $\theta_z$ to its experimental best fit value ($\sim 8^o$), and impose the symmetry in an entire model which includes charged leptons, and many Higgs doublets or standard model singlet heavy scalars, to show that it can make room for the charged lepton mass hierarchies. In addition, we show for the non-tribimaximal value of $\theta_z \neq 0$ within type-I seesaw mechanism enhanced with flavor symmetry that neutrino mass hierarchies can be generated. Furthermore, lepton/baryogenesis can be interpreted via type-II seesaw mechanism within a setup meeting the flavor U(1)-symmetry.Comment: latex, 1 table, 20 pages. Typos are corrected, shortened version to appear in Phys. Rev.

The One-zero Textures of Majorana Neutrino Mass Matrix and Current Experimental Tests

We carry out a complete and systematic study of all the possible one-zero textures for the neutrino mass matrix in light of the recent neutrino oscillation data which hint to a relatively large non-vanishing value for the smallest mixing angle ($\theta_z$). We find that all the six possible one-zero textures are able to accommodate the experimental data, with five cases allowing also for non-invertible mass matrices. We present symmetry realizations for all the one-zero singular and non-singular patterns in type-I and type-II seesaw mechanism schemes.Comment: 35 pages, 14 figures, 8 tables, title change, complete re-analysis with the new updated data, version to appear in PRD. arXiv admin note: substantial text overlap with arXiv:0909.266

Traceless Texture of Neutrino Mass Matrix

We study a neutrino mass matrix texture characterized by a vanishing trace. We highlight the role played by the phases, physical and non-physical, and undergo a thorough phenomenological analysis, first (second) when the non-physical (CP) phases are vanishing, then move on to the general case where all phases exist. Finally we present a theoretical realization of the texture based on $A_5$ non-abelian flavor symmetry.Comment: pdflatex, 22 pages, 6 figures, 4 tables. arXiv admin note: substantial text overlap with arXiv:2308.10985, arXiv:2208.1034

Texture of Two Vanishing Subtraces in Neutrino Mass Matrix and Current Experimental Tests

We present a full phenomenological and analytical study for the neutrino mass matrix characterized by two vanishing $2\times2$ subtraces. We update one past result in light of the recent experimental data. Out of the fifteen possible textures, we find seven cases can accommodate the experimental data instead of eight ones in the past study. We also introduce few symmetry realizations for viable and nonviable textures based on non-abelian ($A_4$ or $S_4$) flavor symmetry within type II seesaw scenario.Comment: pdflatex, 57 pages, 10 tables, 9 figures, version to appear in PR

The (Z_2)^3 symmetry of the non-tri-bimaximal pattern for the neutrino mass matrix

In view of the recent neutrino oscillation data pointing to a non-vanishing value for the smallest mixing angle ($\theta_z$), we derive and find explicit realizations of the $(Z_2)^3$ flavor symmetry which characterizes, for the neutrino mass matrix, uniquely a variant of the tripartite form, originally conceived to lead to the tri-bimaximal mixing with $\theta_z=0$, so that to allow now for a non-tri-bimaximal pattern with non-zero $\theta_z$. We impose this flavor symmetry in a setting including the charged leptons and we see that it can make room, through higher order terms involving new SM-singlet scalars, for the mass hierarchy of charged leptons. Moreover, within type-I seesaw mechanism augmented with the flavor symmetry, certain patterns occurring in both the Dirac and the Majorana neutrino mass matrices can accommodate all types of mass hierarchies in the effective neutrino mass matrix, but no lepton/baryon asymmetry can be generated. Finally, we discuss how type-II seesaw mechanism, when supplemented with the flavor symmetry, could be used to interpret the observed baryon asymmetry through leptogenesis.Comment: 14 pages, 1 table, added references, version to appear in PRD. arXiv admin note: text overlap with arXiv:1008.406