`CP in the Dark' and a Strong First-Order Electroweak Phase Transition

We investigate the potential of the model `CP in the Dark' for providing a strong first-order electroweak phase transition (SFOEWPT) by taking into account all relevant theoretical and experimental constraints. For the derivation of the strength of the phase transition we use the one-loop corrected, daisy-resummed effective potential at finite temperature, implemented in the C++ code BSMPT, to determine the global minimum at the critical temperature. The model `CP in the Dark' provides a dark matter (DM) candidate as well as explicit CP violation in the dark sector. We find a broad range of viable parameter points providing an SFOEWPT. They are within the reach of XENON1T and future invisible Higgs decay searches for DM. `CP in the Dark' also offers SFOEWPT points that feature spontaneous CP violation at finite temperature. Having not only an SFOEWPT that provides the necessary departure from thermal equilibrium, but also a source of additional non-standard CP violation, opens a promising gate towards enabling the generation of the baryon asymmetry of the universe (BAU) through electroweak baryogenesis.