CP-Violation in the $ZZZ$ and $ZWW$ vertices at $e^+e^-$ colliders in Two-Higgs-Doublet Models

TL;DR

This paper explores how CP violation can be measured in Two-Higgs-Doublet Models through one-loop effects on $ZZZ$ and $ZWW$ vertices at $e^+e^-$ colliders, emphasizing the importance of such measurements despite small predicted effects.

Contribution

It introduces CP-sensitive asymmetries in $ZZ$ and $W^+W^-$ production that depend on a weak-basis invariant, linking collider observables to CP violation in the model.

Findings

Predicted CP-violating effects are small due to LHC constraints.

Measuring these effects could indicate a richer scalar sector.

Asymmetries depend on the invariant Im J_2.

Abstract

We discuss possibilities of measuring CP violation in the Two-Higgs-Doublet Model by studying effects of one-loop generated $ZZZ$ and $ZWW$ vertices. We discuss a set of CP-sensitive asymmetries for $ZZ$ and $W^+W^-$ production at linear $e^+e^-$-colliders, that directly depends on the weak-basis invariant Im $J_2$ that parametrises the strength of CP violation. Given the restrictions on this model that follow from the LHC measurements, the predicted effects are small. Pursuing such measurements is however very important, as an observed signal might point to a richer scalar sector.