# Role of Future Lepton Colliders for Fermionic Z-portal Dark Matter

## TL;DR

This paper explores the potential of future lepton colliders, especially with beam polarization, to detect fermionic Z-portal dark matter in the Z-funnel region, which is challenging for direct detection experiments.

## Contribution

It provides a detailed collider analysis for probing Z-funnel dark matter, including systematic uncertainties and the impact of beam polarization.

## Key findings

- Future lepton colliders can effectively probe the Z-funnel dark matter region.
- Beam polarization enhances the sensitivity of mono-photon signals.
- Systematic uncertainties are crucial for realistic collider constraints.

## Abstract

The fermionic Z-portal dark matter model suffers from severe constraints from direct detection experiments. However, a narrow parameter space around the Z-funnel region is beyond the reach due to the resonance annihilation. In this paper, we provide an intriguing collider prospect for probing the Z-funnel dark matter mass range at the future lepton colliders including the beam polarization feature. We have done a comprehensive analysis for mono-photon signal at the colliders for such a dark matter. A realistic estimation for the 90% C.L. constraints with the systematic beam uncertainties has also been provided.