Top Quark as a Dark Portal and Neutrino Mass Generation
  We present a new model for radiatively generating Majorana active neutrino
masses while incorporating a viable dark matter candidate. This is possible by
extending the Standard Model with a single Majorana neutrino endowed with a
dark parity, a colour electroweak singlet scalar, as well as a colour
electroweak triplet scalar. Within this framework, the $up$-type quarks play a
special role, serving as a portal for dark matter, and a messenger for neutrino
mass generation. We consider three benchmark scenarios where the abundance of
dark matter can match the latest experimental results, while generating
neutrino masses in the milli-electronvolt range. We show how constraints from
lepton flavour violation, in particular the branching fraction of $\mu\to
e\gamma$, can place lower bounds on the coupling between our dark matter
candidate and top quarks. Furthermore, we show that this coupling can also be
constrained using collider data from the Tevatron and the LHC.
