Electroweak Baryogenesis at the TeV-scale and the Role of Dark Matter

Restoration of the electroweak symmetry at temperatures around the Higgs mass is linked to tight phenomenological constraints on many baryogenesis scenarios. A potential remedy can be found in mechanisms of electroweak symmetry non-restoration (SNR), in which symmetry breaking is extended to higher temperatures due to new states with couplings to the Standard Model. In this thesis we demonstrate that, given the presence of a second Higgs doublet, SNR can be achieved with just a few additional fermions, which can be acknowledged as potential dark matter candidates consistent with all existing experimental restrictions. We subsequently consider the prospect of electroweak baryogenesis (EWBG) in the context of supersymmetric extensions of the Standard Model. With the idea of SNR, our results demonstrate that the integration of sub-TeV fields allows for a TeV-scale, strongly first-order electroweak phase transition. The proposed models shift the new physics required for EWBG to higher scales, thereby uncovering new parameter spaces to implement EWBG and alleviate experimental conflicts.