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

TL;DR

This paper explores the 'CP in the Dark' model's ability to produce a strong first-order electroweak phase transition, which is crucial for explaining the universe's matter-antimatter asymmetry, while satisfying current experimental constraints.

Contribution

It demonstrates that the 'CP in the Dark' model can achieve a strong first-order electroweak phase transition with viable parameters, including spontaneous CP violation, relevant for baryogenesis.

Findings

Broad parameter space supports SFOEWPT within experimental reach.

Model provides dark matter candidate compatible with XENON1T.

Includes spontaneous CP violation at finite temperature.

Abstract

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.