Dark Sector Assisted Low Scale Leptogenesis from Three Body Decay
  We study the possibility of realising leptogenesis from three body decay,
dark matter (DM) and neutrino mass in a minimal framework. We propose a first
of its kind model to implement the idea of leptogenesis from three body decay
where CP asymmetry arises from interference of multiple $1 \rightarrow 3$
diagrams using resummed propagators along with DM. The standard model is
extended by three heavy singlet fermions, one scalar singlet and one scalar
doublet with appropriate discrete charges. Two of these singlet fermions not
only play non-trivial roles in generating light neutrino mass at radiative
level in scotogenic fashion, but also act as mediators in three body decay of
the third singlet fermion leading to desired CP asymmetry through interference
of such diagrams. With just one additional field compared to the minimal
scotogenic model, we show that successful leptogenesis can occur at a scale as
low as approximately 1 TeV which is much lower than the leptogenesis scale
found for minimal scotogenic model. Also, the realisation of this three body
decay leptogenesis naturally leads to a two component scalar singlet-doublet
dark matter scenario offering a rich phenomenology. Apart from having
interesting interplay of different couplings involved in processes related to
both leptogenesis and dark matter, the model can also be tested at different
experiments due to the existence of its particle spectrum at TeV scale.
