Dilution of dark matter relic density in singlet extension models

We study the dilution of dark matter (DM) relic density caused by electroweak first-order phase transition (FOPT) in singlet extension models, including standard model (xSM), two-Higgs-doublet (2HDM+S) and next-to-minimal supersymmetric (NMSSM). find that these models entropy released strong FOPT can dilute DM to 1/3 at most. Nevertheless, xSM NMSSM where field configure is relevant temperature, always happens before freeze-out, making effect negligible for current density. On other hand, 2HDM+S freeze-out temperature independent FOPT, may salvage some parameter space excluded excessive or direct detections.