11,433 research outputs found
Group and Tri-bimaximal Neutrino Mixing -- A Renormalizable Model
The tetrahedron group has been widely used in studying neutrino mixing
matrix. It provides a natural framework of model building for the tri-bimaximal
mixing matrix. In this class of models, it is necessary to have two Higgs
fields, and , transforming under as 3 with one of them
having vacuum expectation values for the three components to be equal and
another having only one of the components to be non-zero. These specific vev
structures require separating and from communicating with each
other. The clash of the different vev structures for and is the
so called sequestering problem. In this work, I show that it is possible to
construct renormalizable supersymmetric models producing the tri-bimaximal
neutrino mixing with no sequestering problem.Comment: 4 page
Jarlskog Invariant of the Neutrino Mapping Matrix
The Jarlskog Invariant of the neutrino mapping matrix is
calculated based on a phenomenological model which relates the smallness of
light lepton masses and (of ) with the smallness of
violation. For small violating phase in the lepton sector,
is proportional to , but and are proportional
to . This leads to . Assuming
, we find
, consistent with the present experimental
data.Comment: 19 page
Comment on Reparametrization Invariance of Quark-Lepton Complementarity
We study the complementarity between quark and lepton mixing angles (QLC),
the sum of an angle in quark mixing and the corresponding angle in lepton
mixing is . Experimentally in the standard PDG parametrization, two such
relations exist approximately. These QLC relations are accidental which only
manifest themselves in the PDG parametrization. We propose reparametrization
invariant expressions for the complementarity relations in terms of the
magnitude of the elements in the quark and lepton mixing matrices. In the exact
QLC limit, it is found that and . Expressions with deviations
from exact complementarity are obtained. Implications of these relations are
also discussed.Comment: 5 pages and 1 figure. Implications for recent Daya-Bay neutrino data
on theta_{13} discusse
Minimal Modification To The Tri-bimaximal Neutrino Mixing
Current experimental data on neutrino oscillations are consistent with the
tri-bimaximal mixing. If future experimental data will determine a non-zero
and/or find CP violations in neutrino oscillations, there is the need
to modify the mixing pattern. We find that a simple neutrino mass matrix,
resulting from family symmetry breaking with residual and
discrete symmetries respectively for the Higgs sectors generating the charged
lepton and neutrino mass matrices, can satisfy the required modifications. The
neutrino mass matrix is minimally modified with just one additional complex
parameter compared with the one producing the tri-bimaximal mixing. In this
case, the CP violating Jarlskog factor has a simple form
( for real neutrino mass matrix), and also
. We also discuss how this mixing matrix can be tested
experimentally.Comment: Latex 11 pages with no figures. References adde
Unitarity boomerangs of quark and lepton mixing matrices
The most popular way to present mixing matrices of quarks (CKM) and leptons
(PMNS) is the parametrization with three mixing angles and one CP-violating
phase. There are two major options in this kind of parametrizations, one is the
original Kobayashi-Maskawa (KM) matrix, and the other is the Chau-Keung (CK)
matrix. In a new proposal by Frampton and He, a unitarity boomerang is
introduced to combine two unitarity triangles, and this new presentation
displays all four independent parameters of the KM parametrization in the quark
sector simultaneously. In this paper, we study the relations between KM and CK
parametrizations, and also consider the quark-lepton complementarity (QLC) in
the KM parametrization. The unitarity boomerang is discussed in the situation
of the CK parametrization for comparison with that in the KM parametrization in
the quark sector. Then we extend the idea of unitarity boomerang to the lepton
sector, and check the corresponding unitarity boomerangs in the two cases of
parametrizations.Comment: 18 latex pages, 4 figures. Version accepted for publication in PL
Tripartite Neutrino Mass Matrix
The 3 X 3 Majorana neutrino mass matrix is written as a sum of 3 terms, i.e.
M_nu = M_A + M_B + M_C, where M_A is proportional to the identity matrix and
M_B and M_C are invariant under different Z_3 transformations. This M_nu is
very suitable for understanding atmospheric and solar neutrino oscillations,
with sin^2 (2 theta_atm) and tan^2 (theta_sol) fixed at 1 and 0.5 respectively,
in excellent agreement with present data. It has in fact been proposed before,
but only as an ansatz. This paper uncovers its underlying symmetry, thus
allowing a complete theory of leptons and quarks to be constructed.Comment: 9 pages, no figur
Tri-bimaximal Neutrino Mixing and Quark Masses from a Discrete Flavour Symmetry
We build a supersymmetric model of quark and lepton masses based on the
discrete flavour symmetry group T', the double covering of A_4. In the lepton
sector our model is practically indistinguishable from recent models based on
A_4 and, in particular, it predicts a nearly tri-bimaximal mixing, in good
agreement with present data. In the quark sector a realistic pattern of masses
and mixing angles is obtained by exploiting the doublet representations of T',
not available in A_4. To this purpose, the flavour symmetry T' should be broken
spontaneously along appropriate directions in flavour space. In this paper we
fully discuss the related vacuum alignment problem, both at the leading order
and by accounting for small effects coming from higher-order corrections. As a
result we get the relations: \sqrt{m_d/m_s}\approx |V_{us}| and
\sqrt{m_d/m_s}\approx |V_{td}/V_{ts}|.Comment: 27 pages, 1 figure; minor correction
Minimal seesaw model with tri/bi-maximal mixing and leptogenesis
We examine minimal seesaw mechanism in which the masses of light neutrinos
are described with tri/bi-maximal mixing in the basis where the charged-lepton
Yukawa matrix and heavy Majorana neutrino mass matrix are diagonal. We search
for all possible Dirac mass textures which contain at least one zero entry in
matrix and evaluate the corresponding lepton asymmetries. We
present the baryon asymmetry in terms of a single low energy unknown, a
Majorana CP phase to be clued from neutrinoless double beta decay.Comment: 10 pages, 4 figures, revtex4, version to appear in Phys. Lett.
Obtaining the Neutrino Mixing Matrix with the Tetrahedral Group
We discuss various "minimalist'' schemes to derive the neutrino mixing matrix
using the tetrahedral group $A_{4}.
Systematic search for successful lepton mixing patterns with nonzero theta_13
We perform a systematic search for simple but viable lepton mixing patterns.
Our main criterion is that the mixing matrix can be parameterized by three
rotation angles, which are simple fractions of pi. These simple rotation angles
possess exact expressions for their sines and cosines, and often arise in the
flavor symmetry models. All possible parameterizations of the mixing matrix are
taken into account. In total, twenty successful mixing patterns are found to be
consistent with the latest neutrino oscillation data (including the recent T2K
results) in the CP conserving case, whereas fifteen mixing patterns are allowed
in the maximal CP violating case. Potential radiative corrections to the
constant mixing patterns are also calculated by solving the renormalization
group equations.Comment: 10 pages, 4 figures, 2 tables; version to be published in Nuclear
Physics
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