13,256 research outputs found
An Model for Lepton Mass Matrices with Nearly Minimal Texture
We propose a simple extension of the electroweak standard model based on the
discrete symmetry that is capable of realizing a nearly minimal
Fritzsch-type texture for the Dirac mass matrices of both charged leptons and
neutrinos. This is achieved with the aid of additional and
symmetries, one of which can be embedded in . Five complex scalar
singlet fields are introduced in addition to the SM with right-handed
neutrinos. Although more general, the modified texture of the model retains the
successful features of the minimal texture without fine-tuning; namely, it
accommodates the masses and mixing of the leptonic sector and relates the
emergence of large leptonic mixing angles with the seesaw mechanism. For large
deviations of the minimal texture, both quasidegenerate spectrum or inverted
hierarchy are allowed for neutrino masses.Comment: 11pp, 2 figures. v2: vev alignment addressed, additional analysis
performed; to appear in PR
FCNC in the minimal 3-3-1 model revisited
We show that in the minimal 3-3-1 model the flavor changing neutral currents
(FCNCs) do not impose necessarily strong constraints on the mass of the
of the model if we also consider the neutral scalar contributions to
such processes, like the neutral mesons mass difference and rare semileptonic
decays. We first obtain numerical values for all the mixing matrices of the
model i.e., the unitary matrices that rotate the left- and right-handed quarks
in each charge sector which give the correct mass of all the quarks and the CKM
mixing matrix. Then, we find that there is a range of parameters in which the
neutral scalar contributions to these processes may interfere with those of the
, implying this vector boson may be lighter than it has been thought.Comment: Extended version including the effect of a pseudoscalar. 37 pags. and
12 figures. New references added. Version matches the published versio
Quasi-Dirac neutrinos and solar neutrino data
We present an analysis of the solar neutrino data in the context of a
quasi-Dirac neutrino model in which the lepton mixing matrix is given at tree
level by the tribimaximal matrix. When radiative corrections are taken into
account, new effects in neutrino oscillations, as , appear.
This oscillation is constrained by the solar neutrino data. In our analysis, we
have found an allowed region for our two free parameters and .
The radiative correction, , can vary approximately from to and the calculated fourth mass eigenstate, , 0.01 eV
to 0.2 eV at 2 level. These results are very similar to the ones
presented in the literature.Comment: 24 pages, 7 figures and 2 tables. Results and conclusion unchanged.
Version published in EPJC. Figures improve
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