Two-step strongly first-order electroweak phase transition modified FIMP
  dark matter, gravitational wave signals, and the neutrino mass
  We study a dynamical freeze-in production of the dark matter considering the
electroweak phase transition history of the Universe. The kinematical
thresholds of the decay and scattering processes for the dark matter production
can be altered by the temperature dependent thermal masses of particles, which
might lead to enhancement or reduction of the dark matter relic abundance. The
second-stage strongly first-order electroweak phase transition (SFOEWPT)
triggered by the hidden scalars can be probed at colliders and the
gravitational wave detectors. The two-step SFOEWPT modified late decay FIMP
dark matter is accomplished with a Dirac neutrino mass explanation in the
scotogenic model.
