464 research outputs found
Mass Limit for Light Flavon with Residual Symmetry
We present a modified Altarelli and Feruglio model where an additional
singlet-prime flavon is introduced. In this model, non-zero is given by this additional singlet-prime flavon which breaks
tri-bimaximal mixing. In the framework of the supersymmetry with
symmetry, we obtain vacuum expectation values (VEVs) and VEV alignments of
flavons through driving fields. It is considered that flavon induces
distinctive flavor violating process if flavon mass is light. Assuming mass of
SUSY particles are sufficiently heavy so that the SUSY contributions can be
negligible, we discuss the flavor violating Yukawa interaction through flavon
exchange in the charged lepton sector. According to the potential analysis, the
VEV of flavon breaks down to in the charged lepton sector and
relation among flavon masses is determined. Thanks for the residual
symmetry, many lepton flavor violating decay modes are forbidden except for
and . A mass
limit of the flavon from these three-body decay modes is ~GeV taking into
account the current experimental lower bounds at the Belle experiment. In our
model, we predict a ratio of the branching ratios and by using known charged lepton
masses. We also find that the production cross section for the flavon can be
fb. Thus the flavon would be found at the LHC run 2 by
searching for 4-tau lepton signal.Comment: 14 pages, final versio
Model for the Lepton Flavor Structure and the Strong Problem
We present a model with lepton flavor symmetry which
explains the origin of the lepton flavor structure and also solves the strong
problem. Standard model gauge singlet fields, so-called "flavons", charged
under the symmetry are introduced and are coupled with
the lepton and the Higgs sectors. The flavon vacuum expectation values (VEVs)
trigger spontaneous breaking of the symmetry. The
breaking pattern of the accounts for the tri-bimaximal neutrino mixing
and the deviation from it due to the non-zero angle, and the
breaking of the gives rise to a pseudo-Nambu-Goldstone boson,
axion, whose VEV cancels the QCD term. We investigate the breaking of
the symmetry through an analysis on the scalar potential
and further discuss the properties of the axion in the model, including its
decay constant, mass and coupling with photons. It is shown that the axion
decay constant is related with the right-handed neutrino mass through the
flavon VEVs. Experimental constraints on the axion and their implications are
also studied.Comment: 13 pages, final version, minor modification
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