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 are the 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 CP . Therefore, if δ CP = π/2 is established, our minimalistic scheme may still be viable provided we allow more number of parameters in 'm e '. * roopam.sinha@saha.ac.in † rome.samanta@saha.ac.in ‡ ambar.ghosal@saha.ac.in 1 arXiv:1508.05227v2 [hep-ph]

Singlet Fermion Assisted Dominant Seesaw with Lepton Flavor and Number Violations and Leptogenesis

“…Naturally small value of µ S in the ′ t Hooft sense [217] brings down the inverse seesaw mechanism to the TeV scale without having the need to fine tune the associated Dirac mass matrix or Yukawa couplings. The presence of texture zeros in the constituent matrices of different types of seesaw formulas have been investigated consistent with neutrino oscillation data [200,201,202,204,205].…”

“…Possible presence of specific textures of constituent matrices in the context of inverse, linear or type-I seesaw models have been also explored [199,200,201,202,203,204,205,206]. More recently the hybrid seesaw ansatz for matter parity conserving SO (10) has been applied to explain neutrino masses, dark matter, and baryon asymmetrty of the universe without invoking any texture or intermediate scale in the non-supersymmetric SO(10) ramework [207].…”

Fermion masses and mixings in an extended SM based on A4 flavor symmetry with the linear seesaw for majorana neutrino

“…However, the mass scale of the right-handed neutrinos, in the canonical seesaw mechanisms, is too high that cannot be achieved by the near future experiments. In the linear seesaw mechanism, the smallness of neutrino masses generate as a result of physics at TeV scale which can be verified by LHC [4][5][6][7][8][9].…”

Simple A4 models for dark matter stability with texture zeros

“…These textures have been extensively studied [5,[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Here for completeness we present some results and give an estimate of the radiative correction for the neutrinoless double beta decay effective mass parameter.…”