A Unified Hidden-Sector-Electroweak Model, Paraphotons and the X-Boson
  Our contribution sets out to investigate the phenomenology of a gauge model based on an $SU_{L}(2) \times U_{R}(1)_{J} \times U(1)_{K}$-symmetry group. The model can accommodate in its distinct phases - by virtue of different symmetry-breaking patterns - a candidate to a heavy $Z'$-boson at the TeV-scale and the recently discussed $17 \, \mbox{MeV}$ X-boson that may bring about a new physics at the $\mbox{MeV}$-scale. Furthermore, the para-photon of the dark matter sector and the candidate to the so-called dark photon can also be described in the scenario we are endeavoring to set up in this paper. In the $Z'$-scenario, the extended Higgs sector introduces a heavy scalar whose mass lies in the region $1.2-3.7 \, \mbox{TeV}$, while that the lower energy scale scenario presents a light scalar with mass in the interval $1.9-19 \, \mbox{GeV}$. The fermionic sector includes an exotic candidate to dark matter that mixes with the right-neutrino component in the Higgs sector, so that the whole field content yields the cancellation of the U(1)-anomaly. The masses are fixed according to the particular way the symmetry breaking takes place. In view of the possible symmetry breakdown patterns, we study the phenomenological implications in both scenarios of high- and low-energy scales. As examples, we consider the scattering of Standard Model matter into dark sector constituents intermediated by the $Z'$-boson in the $\mbox{TeV}$-scale, and the corresponding scattering intermediated by a lightest boson in the lower scale physics. Furthermore, we obtain the magnetic dipole momentum (MDM) of the exotic fermion and the transition MDM due to the mixing with the right-neutrino. 
M. J. Neves, J. A. Helay\"el-Neto
hep-ph hep-th