CP Violation and Electroweak Baryogenesis in Extensions of the Standard Model

TL;DR

The paper addresses the need for reliable CP-violating sources in electroweak baryogenesis beyond the Standard Model by introducing a general framework that tracks space-dependent mass matrices $M(z)$ across a bubble wall and computes CP-violating currents $J_\pm$ and the axial source $S_A$ via quantum interference, valid for all wall thickness regimes through a form factor ${\cal I}$. It provides explicit results in the two-Higgs-doublet model, deriving $S_A$ in the thick-wall limit as $S_A \approx -\frac{N_c}{2\pi^2} \gamma_w v_w T m^2 \partial_z \theta$ (up to corrections), highlighting the role of interference and transport. The method reconciles and surpasses previous thin/thick-wall approaches, offering a robust, general tool suitable for models with large flavor mixing or supersymmetry and for Monte Carlo studies of baryogenesis. Overall, this framework enables accurate, regime-spanning EWBG calculations by directly incorporating quantum-coherent CP violation and plasma interactions into the generation of the baryon asymmetry.

Abstract

We develop a new and general method to calculate the effects of \cp\ violation from extensions of the standard model on the mechanism of electroweak baryogenesis. We illustrate its applicability in the framework of two-higgs doublet models.