Rome Samanta

Probing texture zeros with scaling ansatz in inverse seesaw

A bstractWe investigate neutrino mass matrix phenomenology involving scaling ansatz and texture zeros adhering inverse seesaw mechanism. It is seen that four is the maximum number of zeros in mD and μ to obtain viable phenomenology. Depending upon the generic nature of the effective neutrino mass matrices we classify all the emerged matrices in four categories. One of them is ruled out phenomenologically due to inappropriate value of reactor mixing angle after breaking of the scaling ansatz. The mass ordering is inverted in all cases. One of the distinguishable feature of all these categories is the vanishingly small value of CP violation measure JCP due to small value of δCP. Thus those categories will be ruled out if CP violation is observed in the leptonic sector in future experiments.

Maximal zero textures in Linear and Inverse seesaw

Abstract We investigate Linear and Inverse seesaw mechanisms with maximal zero textures of the constituent matrices subjected to the assumption of non-zero eigenvalues for the neutrino mass matrix m ν and charged lepton mass matrix m e . If we restrict to the minimally parametrized non-singular ‘ m e ’ (i.e., with maximum number of zeros) it gives rise to only 6 possible textures of m e . Non-zero determinant of m ν dictates six possible textures of the constituent matrices. We ask in this minimalistic approach, what phenomenologically allowed maximum zero textures are possible. It turns out that Inverse seesaw leads to 7 allowed two-zero textures while the Linear seesaw leads to only one. In Inverse seesaw, we show that 2 is the maximum number of independent zeros that can be inserted into μ S to obtain all 7 viable two-zero textures of m ν . On the other hand, in Linear seesaw mechanism, the minimal scheme allows maximum 5 zeros to be accommodated in ‘m’ so as to obtain viable effective neutrino mass matrices ( m ν ). Interestingly, we find that our minimalistic approach in Inverse seesaw leads to a realization of all the phenomenologically allowed two-zero textures whereas in Linear seesaw only one such texture is viable. Next, our numerical analysis shows that none of the two-zero textures give rise to enough CP violation or significant δ C P . Therefore, if δ C P = π / 2 is established, our minimalistic scheme may still be viable provided we allow larger number of parameters in ‘ m e ’.

Evaluation of the Majorana phases of a general Majorana neutrino mass matrix: Testability of hierarchical flavour models

Abstract We evaluate the Majorana phases for a general 3 × 3 complex symmetric neutrino mass matrix on the basis of Mohapatra–Rodejohanns phase convention using the three rephasing invariant quantities I 12 , I 13 and I 23 proposed by Sarkar and Singh. We find them interesting as they allow us to evaluate each Majorana phase in a model independent way even if one eigenvalue is zero. Utilizing the solution of a general complex symmetric mass matrix for eigenvalues and mixing angles we determine the Majorana phases for both the hierarchies, normal and inverted, taking into account the constraints from neutrino oscillation global fit data as well as bound on the sum of the three light neutrino masses ( Σ i m i ) and the neutrinoless double beta decay ( β β 0 ν ) parameter | m 11 | . This methodology of finding the Majorana phases is applied thereafter in some predictive models for both the hierarchical cases (normal and inverted) to evaluate the corresponding Majorana phases and it is shown that all the sub cases presented in inverted hierarchy section can be realized in a model with texture zeros and scaling ansatz within the framework of inverse seesaw although one of the sub cases following the normal hierarchy is yet to be established. Except the case of quasi degenerate neutrinos, the methodology obtained in this work is able to evaluate the corresponding Majorana phases, given any model of neutrino masses.

Extended scaling and residual flavor symmetry in the neutrino Majorana mass matrix

The residual symmetry approach, along with a complex extension for some flavor invariance, is a powerful tool to uncover the flavor structure of the 3

Baryon asymmetry via leptogenesis in a neutrino mass model with complex scaling

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Generalized

× 3 neutrino Majorana mass matrix

in scaling neutrino Majorana mass matrix and baryogenesis via flavored leptogenesis

M_\nu