Two-step strongly first-order electroweak phase transition modified FIMP dark matter, gravitational wave signals, and the neutrino mass

We study the dynamical freeze-in production of dark matter considering the electroweak phase transition history of the Universe. The kinematical thresholds of the decay and scattering processes for dark matter production can be altered by the temperature-dependent thermal masses of particles, which might lead to an 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 he probed at colliders and gravitational wave detectors. Two-step SFOEWPT modified late decay feebly interacting massive particle dark matter is accomplished with a Dirac neutrino mass explanation in the scotogenic model.