398 research outputs found
Hierarchical majorana neutrinos from democratic mass matrices
In this paper, we obtain the light neutrino masses and mixings consistent
with the experiments, in the democratic texture approach. The essential ansatz
is that are assumed to transform as "right-handed fields" under the symmetry. The symmetry breaking terms
are assumed to be diagonal and hierarchical. This setup only allows the normal
hierarchy of the neutrino mass, and excludes both of inverted hierarchical and
degenerated neutrinos.
Although the neutrino sector has nine free parameters, several predictions
are obtained at the leading order. When we neglect the smallest parameters
and , all components of the mixing matrix are expressed by the masses of light neutrinos and charged leptons. From
the consistency between predicted and observed , we obtain the
lightest neutrino masses = (1.1 1.4) meV, and the effective mass
for the double beta decay \vev{m_{ee}} \simeq 4.5 meV.Comment: 14 pages, 1 table, substantially revised versio
Flavor structure from misalignment of inner products in noncommutative geometry
In this letter, we consider an idea that induces flavor structure from inner
products in noncommutative geometry. Assuming proper components of vectors
in enlarged representation space for fermions, we can induce the
waterfall texture for Yukawa matrices retaining gauge interactions are
universal. The hierarchy of the Yukawa interactions is a consequence of
"misalignment" between the vectors and .Comment: 6pages, 1 table, the final version to appear in JHE
Conditions of general symmetry in an arbitrary basis and TM mixing for the minimal type-I seesaw mechanism
In this paper, using a formula for the minimal type-I seesaw mechanism by
decomposition, conditions of general -invariance of the
neutrino mass matrix is obtained for Lagrangian parameters in an arbitrary
basis. The conditions are found to be
for the -symmetric and -antisymmetric part of a Yukawa matrix
and the right-handed neutrino mass matrix . In other words, the
symmetric and antisymmetric part of must be proportional to those of
the quantity .
Since the eigenvectors of the generator are orthogonal, we can analyze
the eigenvectors and mass eigenvalues of for a
-symmetric . Two eigenvectors of coincide
with any of those of , and the remaining one is a vector orthogonal to them. Furthermore, if the Yukawa matrix does not have
the symmetry, two nonzero neutrino masses are concisely represented.
These results are applied to three symmetries, the
symmetry, the TM mixing, and the magic symmetry which predicts the
TM mixing. In particular, for the TM mixing, the magic
(anti-)symmetric Yukawa matrix with is phenomenologically
rejected because it predicts or .Comment: 21 page
- β¦