Electroweak Baryogenesis driven by Extra Top Yukawa Couplings

Abstract

We study electroweak baryogenesis driven by the top quark in a general two Higgs doublet model with flavor-changing Yukawa couplings, keeping the Higgs potential $CP$ invariant. With Higgs sector couplings and the additional top Yukawa coupling ${\rho }_{tt}$ all of $\mathcal{O}$(1), one naturally has sizable $CP$ violation that fuels the cosmic baryon asymmetry. Even if ${\rho }_{tt}$ vanishes, the favor-changing coupling ${\rho }_{tc}$ can still lead to successful baryogenesis. Phenomenological consequences such as $t\to ch$, $\tau \to \mu \gamma$, electron electric dipole moment, $h\to \gamma \gamma$, and $hhh$ coupling are discussed.

Comments: 5 pages, 3 figures; v2: updated to match version published in PLB