Discovery Prospects for Electron and Neutron Electric Dipole Moments in the General Two Higgs Doublet Model

TL;DR

This paper explores how the general two Higgs Doublet Model can produce observable electron and neutron electric dipole moments, providing potential signals for new physics beyond the Standard Model, especially in the context of baryogenesis.

Contribution

It demonstrates that the g2HDM can generate detectable EDMs while evading current constraints, and proposes a cancellation mechanism for neutron EDM.

Findings

eEDM may reach $10^{-30}\,e$ cm

nEDM could be as low as $10^{-27}\,e$ cm

Future experiments could probe nEDM down to $10^{-28}\,e$ cm

Abstract

Baryon asymmetry of the Universe offers one of the strongest hints for physics Beyond the Standard Model (BSM). Remarkably, in the general two Higgs Doublet Model (g2HDM) that possesses a second set of Yukawa matrices, one can have electroweak baryogenesis (EWBG) while the electron electric dipole moment (eEDM) is evaded by a natural flavor tuning that echoes SM. We show that eEDM may first emerge around $10^{-30}\,e$ cm or so, followed by neutron EDM (nEDM) down to $10^{-27}\,e$ cm. We illustrate a cancellation mechanism for nEDM itself, which in turn can be probed when a facility capable of pushing down to $10^{-28}\,e$ cm becomes available.