High Scale Electroweak Phase Transition: Baryogenesis & Symmetry Non-Restoration

TL;DR

This paper investigates a high-scale electroweak phase transition that enables baryogenesis without symmetry restoration, leveraging enhanced Yukawa couplings and additional scalars to avoid baryon asymmetry washout.

Contribution

It proposes a novel high-scale electroweak baryogenesis scenario with persistent symmetry breaking and flavor physics connections, avoiding washout issues.

Findings

High-scale phase transition with non-restoration of symmetry.

Enhanced Yukawa couplings induce time-dependent CP violation.

Additional scalars prevent baryon asymmetry washout.

Abstract

We explore the possibility that the electroweak phase transition happens at a scale much higher than the electroweak scale today. In this context, high scale CP-violating sources for electroweak baryogenesis are not constrained by low-energy experiments. We propose a scenario of high-scale electroweak baryogenesis linked to flavour physics. This scenario allows for a period of enhanced Yukawa couplings during the evolution of the universe, which source time-dependent CP violation. The electroweak symmetry is never restored after the high-scale phase transition due to negative contributions to the Higgs thermal mass squared from a large number of additional electroweak-scale neutral scalars coupling to the Higgs. As a result, the washout of the baryon asymmetry is avoided.