Lepton-Flavored Electroweak Baryogenesis

TL;DR

This paper investigates how CP-violation in the leptonic sector within a two Higgs doublet model can generate the observed baryon asymmetry during the electroweak phase transition, linking it to observable Higgs decays.

Contribution

It introduces a lepton-flavored electroweak baryogenesis mechanism driven by CP-violation in the leptonic Yukawa sector, connecting baryogenesis with specific Higgs decay signatures.

Findings

Baryon asymmetry can be generated within current experimental constraints.

CP-violating effects are linked to Higgs decays h→ττ and h→τμ.

Parameter space is compatible with existing decay and EDM bounds.

Abstract

We explore lepton-flavored electroweak baryogenesis, driven by CP-violation in leptonic Yukawa sector, using the $\tau-\mu$ system in the two Higgs doublet model as an example. This setup generically yields, together with the flavor-changing decay $h\to \tau \mu$, a tree-level Jarlskog-invariant that can drive dynamical generation of baryon asymmetry during a first-order electroweak phase transition and results in CP-violating effect in the decay $h\to \tau\tau$. We find that the observed baryon asymmetry can be generated in parameter space compatible with current experimental results for the decays $h\to \tau \mu$, $h\to \tau\tau$ and $\tau \rightarrow \mu \gamma$, as well as the present bound on the electric dipole moment of the electron. The baryon asymmetry generated is intrinsically correlated with the CP-violating decay $h\to \tau\tau$ and the flavor-changing decay $h\to \tau\mu$, which thus may serve as "smoking guns" to test lepton-flavored electroweak baryogenesis.