From inflation to cosmological electroweak phase transition with a complex scalar singlet

Abstract

We investigate the possibility of addressing inflation, a strongly first-order electroweak phase transition (SFOEWPT) together with the dark matter (DM) explanation simultaneously. We study the Higgs-portal real scalar singlet model and the complex scalar singlet model. In both models, the SFOEWPT can occur through two-step patterns in which the magnitude of the Higgs-singlet quartic couplings meets the slow-roll condition of inflation. The Higgs-portal real scalar singlet model cannot address the correct DM relic density together with the explanation of inflation and SFOEWPT. Taking advantage of the cancellation in the DM-nucleon interaction, the weakly interacting massive particles DM can saturate the correct DM relic abundance in the complex scalar singlet model, with the pseudoscalar being the DM candidate after the global U(1) symmetry is broken. The key ingredient in obtaining the successful inflation and the SFOEWPT is that the magnitude of the scalar quartic couplings should be relatively lower. Because the cancellation of the DM-nucleon scattering amplitude mediated by mixtures of SM Higgs and other heavy scalars can occur to a different extent in many models, we can expect that the features being explored here are general.