2,990 research outputs found
Understanding for flavor physics in the lepton sector
In this paper, we give a model for understanding flavor physics in the lepton
sector--mass hierarchy among different generations and neutrino mixing pattern.
The model is constructed in the framework of supersymmetry, with a family
symmetry . There are two right-handed neutrinos introduced for seesaw
mechanism, while some standard model(SM) gauge group singlet fields are
included which transforms non-trivially under family symmetry. In the model,
each order of contributions are suppressed by compared to the
previous one. In order to reproduce the mass hierarchy, and
, and are obtained
at leading-order(LO) and next-to-leading-order(NLO) respectively, while
electron can only get its mass through
next-to-next-to-next-to-leading-order(NNNLO) contributions. For neutrino mixing
angels, are
i.e. Bi-maximal mixing pattern as first approximation, while higher order
contributions can make them consistent with experimental results. As
corrections for and originate from the same
contribution, there is a relation predicted for them
. Besides, deviation from
for should have been as large as
deviation from 0 for if it were not the former is suppressed by a
factor 4 compared to the latter.Comment: version to appear in Phys. Rev.
On the four-zero texture of quark mass matrices and its stability
We carry out a new study of quark mass matrices (up-type) and
(down-type) which are Hermitian and have four zero entries, and
find a new part of the parameter space which was missed in the previous works.
We identify two more specific four-zero patterns of and
with fewer free parameters, and present two toy flavor-symmetry
models which can help realize such special and interesting quark flavor
structures. We also show that the texture zeros of and
are essentially stable against the evolution of energy scales in
an analytical way by using the one-loop renormalization-group equations.Comment: 33 pages, 4 figures, minor comments added, version to appear in Nucl.
Phys.
Localization of gauge vector field on flat branes with five-dimension (asymptotic) AdS spacetime
In order to localize gauge vector field on Randall-Sundrum-like
braneworld model with infinite extra dimension, we propose a new kind of
non-minimal coupling between the gauge field and the gravity. We propose
three kinds of coupling methods and they all support the localization of zero
mode. In addition, one of them can support the localization of massive modes.
Moreover, the massive tachyonic modes can be excluded. And our method can be
used not only in the thin braneword models but also in the thick ones.Comment: Added acknowledgments to the refree. Appeared on JHE
The effective neutrino mass of neutrinoless double-beta decays: how possible to fall into a well
If massive neutrinos are the Majorana particles and have a normal mass
ordering, the effective mass term of a neutrinoless
double-beta () decay may suffer significant cancellations among
its three components and thus sink into a decline, resulting in a "well" in the
three-dimensional graph of against the smallest
neutrino mass and the relevant Majorana phase . We present a new
and complete analytical understanding of the fine issues inside such a well,
and discover a novel threshold of in terms of the
neutrino masses and flavor mixing angles: in connection with and . This threshold point, which links the
{\it local} minimum and maximum of , can be used to
signify observability or sensitivity of the future -decay
experiments. Given current neutrino oscillation data, the possibility of
is found to be
very small.Comment: 9 pages, 3 figures, version to appear in Eur. Phys. J.
Minimal modifications to the Tri-Bimaximal neutrino mixing
In light of the observation of a relatively large , the ever
popular Tri-Bimaximal (TBM) neutrino mixing which predicts a vanishing
needs modifications. In this paper, we shall discuss the
possibility of modifying it in a minimal way to fulfil this task. In the first
part, a neutrino mass matrix with three independent parameters, which leads to
the TM2 mixing, is obtained by analogy with that for the TBM mixing. In the
second part, a model that can realize the TM2 mixing is constructed with flavor
symmetries . It is the
variant of a model that gives the TBM mixing, with only one more flavon field
included. Furthermore, the imaginary vacuum expectation value (VEV) of this
flavon breaks the imposed CP symmetry and results in and
the maximal CP violation. This VEV is also helpful for providing a large enough
CP asymmetry required by the leptogenesis mechanism. Besides, this model
building approach can be generalized to the TM1 mixing in a straightforward
way.Comment: 21 pages, version accepted for publication in JHE
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