# CP-violating Dark Photon Interaction

## TL;DR

This paper explores CP-violating interactions of a dark photon within a non-abelian kinetic mixing framework, proposing experimental tests via electric dipole moments and collider jet correlations, with current EDM limits providing the strongest constraints.

## Contribution

It introduces a novel effective field theory model for CP-violating dark photon interactions involving dimension five operators and discusses experimental detection prospects.

## Key findings

- Electron EDM measurements impose strong limits on CPV interactions.
- High-energy collider signatures via jet correlations are theoretically possible.
- Observation of CPV asymmetry at colliders is challenging in practice.

## Abstract

We introduce a scenario for CP-violating (CPV) dark photon interactions in the context of non-abelian kinetic mixing. Assuming an effective field theory that extends the Standard Model (SM) field content with an additional $U(1)$ gauge boson ($X$) and a $SU(2)_L$ triplet scalar, we show that there exist both CP-conserving and CPV dimension five operators involving these new degrees of freedom and the SM $SU(2)_L$ gauge bosons. The former yields kinetic mixing between the $X$ and the neutral $SU(2)_L$ gauge boson (yielding the dark photon), while the latter induces CPV interactions of the dark photon with the SM particles. We discuss experimental probes of these interactions using searches for permanent electric dipole moments (EDMs) and di-jet correlations in high-energy $pp$ collisions. It is found that the experimental limit on the electron EDM currently gives the strongest restriction on the CPV interaction. In principle, high energy $pp$ collisions provide a complementary probe through azimuthal angular correlations of the two forward tagging jets in vector boson fusion. In practice, observation of the associated CPV asymmetry is likely to be challenging.