Debasish Borah, Rathin Adhikari
We study a simple extension of Standard Model where the gauge group is
extended by an additional $U(1)_X$ gauge symmetry. Neutrino mass arise both at
tree level as well as radiatively by the anomaly free addition of one singlet
fermion $N_R$ and two triplet fermions $\Sigma_{1R}, \Sigma_{2R}$ with suitable
Higgs scalars. The spontaneous gauge symmetry breaking is achieved in such a
way which results in a residual $Z_2$ symmetry and hence providing a stable
cold dark matter candidate. We study the possible dark matter candidates in
this model by incorporating the constraints from cosmology as well as direct
detection experiments. We discuss both low and high mass (from GeV to the TeV
scale) regimes of fermionic and scalar dark matter candidates in the model. We
show that scalar dark matter relic density, although not significantly affected
by the presence or absence of annihilation into $U(1)_X$ gauge boson pairs, is
however affected by choice of $U(1)_X$ gauge charges. We discuss the neutrino
mass phenomenology and its compatibility with the allowed dark matter mass
ranges and also comment on the implications of the model on Higgs signatures at
colliders including those related to fourth fermion generation.
View original:
http://arxiv.org/abs/1202.2718
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