CP Violation for the Heavens and the Earth

TL;DR

This paper explores how additional Yukawa couplings in a two Higgs doublet model can drive electroweak baryogenesis, linking flavor physics, Higgs phenomenology, and electric dipole moments to explain the cosmic matter-antimatter asymmetry.

Contribution

It introduces a novel mechanism where extra Yukawa couplings enable electroweak baryogenesis within a two Higgs doublet framework, considering experimental constraints and phenomenological implications.

Findings

Extra Yukawa couplings can generate sufficient baryon asymmetry.

Flavor-changing couplings serve as backups for CP violation.

Phenomenological signals include modifications in Higgs and flavor physics.

Abstract

Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling $\rho_{tt}$ can fuel the cosmic baryon asymmetry through the $\lambda_t\,{\rm Im}\,\rho_{tt}$ product, with flavor-changing $\rho_{tc}$ coupling as backup. The impressive ACME 2018 bound on the electron electric dipole moment calls for an extra electron coupling $\rho_{ee}$ for exquisite cancellation among dangerous diagrams, broadening the baryogenesis solution space. The mechanism suggests that extra Yukawa couplings echo the hierarchical structure of standard Yukawa couplings. Phenomenological consequences in Higgs search and flavor physics are discussed, with $\mu$ and $\tau$ EDM touched upon.