Zusammenfassung
Two puzzling facts of our time are the observed patterns in the fermion
masses and mixings and the existence of non-baryonic dark matter, which are
both often associated with extensions of the Standard Model at higher energy
scales. In this paper, we consider a solution to these two problems with the
flavour symmetry \$A\_4Z\_2\mathbb
Z\_2^\prime\$, in a model which has been shown before to explain large leptonic
mixings with a specific texture. The model contains 3 generations of
\$SU(2)\_L\$-doublet scalar fields, arranged as an \$A\_4\$-triplet, that
spontaneously break the electroweak symmetry, and a "dark sector" of \$\mathbb
Z\_2\$-odd fields, containing one Majorana neutrino and an \$\mathbb
A\_4\$-triplet \$SU(2)\_L\$-doublet scalar field, the lightest of which provides a
candidate for dark matter.
Concerning the \$Z\_2\$-even scalar fields, compared to the Standard
Model, we predict additional fields with masses at the electroweak scale. We
therefore investigate present phenomenological constraints from lepton flavour
violation experiments, obtaining a lower bound on the extra scalar masses of
140 GeV. Furthermore we consider the oblique parameters, Higgs boson decay
properties and possible flavour violating signals at the LHC.
Concerning the "dark sector", we study bounds from dark matter search
experiments and identify the parameter space of the dark matter candidate that
is compatible with the observed relic density. We find two allowed mass ranges
for the dark matter within which the experimental constraints can be
accommodated: the low-mass range is from 47 GeV to 74 GeV and the high-mass
range is from 600 GeV and 3.6 TeV.
Nutzer