When Freeze-out Precedes Freeze-in: Sub-TeV Fermion Triplet Dark Matter
  with Radiative Neutrino Mass
  We propose a minimal predictive scenario for dark matter and radiative
neutrino mass where the relic abundance of dark matter is generated from a
hybrid setup comprising of both thermal freeze-out as well as non-thermal
freeze-in mechanisms. Considering three copies of fermion triplets and one
scalar doublet, odd under an unbroken $\mathbb{Z}_2$ symmetry, to be
responsible for radiative origin of neutrino mass, we consider the lightest
fermion triplet as a dark matter candidate which remains under-abundant in the
sub-TeV regime from usual thermal freeze-out. Late decay of the
$\mathbb{Z}_2$-odd scalar doublet into dark matter serves as the non-thermal
(freeze-in) contribution which not only fills the thermal dark matter deficit,
but also constrains the mother particle's parameter space so that the correct
relic abundance of dark matter is generated. Apart from showing interesting
differences from the purely freeze-out and purely freeze-in dark matter
scenarios, the model remains testable through disappearing charge track
signatures at colliders, observable direct and indirect detection rates for
dark matter and prediction of almost vanishing lightest neutrino mass.
