Does the Electron EDM Preclude Electroweak Baryogenesis ?

Abstract

Electroweak baryogenesis (EWBG) constitutes a theoretically compelling and experimentally testable mechanism for explaining the origin of the baryon asymmetry of the universe (BAU). New results for the electric dipole moment (EDM) of the electron place significant constraints on the beyond Standard Model CP-violation needed for successful EWBG. Using a specific model illustration, we show how new developments in EWBG quantum transport theory that include CP-violating sources first order in gradients imply more relaxed EDM constraints -- and thereby greater EWBG viability -- than implied by previous approximation formulations. We also illustrate how these developments enable a more realistic treatment of CP-conserving interactions that can also have a decisive impact on the predicted BAU.

Figures (4)

• Figure 1: Left handed quark density $n_L = (4 c_T + 5c_Q) n_{H_1}$ for the VIA (blue) and VR (red) approaches. The bubble exterior (interior) corresponds to $z<0$ ($z>0$).
• Figure 2: The obtained BAU $n_B$ as a function of $m_{H_1}$ (with fixed $m_{H_2} = 1.32 T$) (top) and the portal coupling $a_2$ (bottom) for VR and VIA approaches.
• Figure 3: Constraints on the CPV phase $\delta_\Sigma$ as a function of the physical $T=0$ mass $m_{h_2}$ with the other parameters fixed. The solid red (blue) band gives the VR (VIA) prediction. The shaded region above the solid (dashed) black line is excluded by the current (previous) electron EDM limit Alarcon:2022ero (ACME:2018yjb).
• Figure 4: Leading-order graphs contributing to the self-energy terms in the Boltzmann equations, corresponding to (a) thermal mass correction from coherent forward scattering, and (b) non-forward scattering ($\eta\phi \leftrightarrow \eta \phi$) and annihilation ($\eta \eta^\dagger \leftrightarrow \phi \phi$).