# Electric Dipole Moments From Dark Sectors

## TL;DR

This paper investigates how electric dipole moments (EDMs) can reveal new $CP$-violating physics in hidden dark sectors coupled to the Standard Model through various portals, highlighting the potential for EDMs to probe dark sector interactions.

## Contribution

It demonstrates that dark sector interactions can induce measurable EDMs via different portals, with detailed calculations of loop orders and sensitivity to portal couplings.

## Key findings

- Electron EDM can be generated through gauge kinetic mixing at five loops.
- Weak interactions and Higgs/neutrino portals lead to two-loop contributions to EDMs.
- EDMs can serve as sensitive probes of dark sector couplings, complementing collider searches.

## Abstract

We examine the sensitivity of electric dipole moments (EDMs) to new $CP$-violating physics in a hidden (or dark) sector, neutral under the Standard Model (SM) gauge groups, and coupled via renormalizable portals. In the absence of weak sector interactions, we show that the electron EDM can be induced purely through the gauge kinetic mixing portal, but requires five loops, and four powers of the kinetic mixing parameter $\epsilon$. Allowing weak interactions, and incorporating the Higgs and neutrino portals, we show that the leading contributions to $d_e$ arise at two-loop order, with the main source of $CP$-violating being in the interaction of dark Higgs and heavy singlet neutrinos. In such models, EDMs can provide new sensitivity to portal couplings that is complementary to direct probes at the intensity frontier or high energy colliders.