Sterile neutrino portal to Dark Matter I: The $U(1)_{B-L}$ case
  In this paper we explore the possibility that the sterile neutrino and Dark
Matter sectors in the Universe have a common origin. We study the consequences
of this assumption in the simple case of coupling the dark sector to the
Standard Model via a global $U(1)_{B-L}$, broken down spontaneously by a dark
scalar. This dark scalar provides masses to the dark fermions and communicates
with the Higgs via a Higgs portal coupling. We find an interesting interplay
between Dark Matter annihilation to dark scalars - the CP-even that mixes with
the Higgs and the CP-odd which becomes a Goldstone boson, the Majoron - and
heavy neutrinos, as well as collider probes via the coupling to the Higgs.
Moreover, Dark Matter annihilation into sterile neutrinos and its subsequent
decay to gauge bosons and quarks, charged leptons or neutrinos lead to indirect
detection signatures which are close to current bounds on the gamma ray flux
from the galactic center and dwarf galaxies.
