EFT analysis of leptophilic dark matter at future electron-positron colliders in the mono-photon and mono-$Z$ channels

TL;DR

This paper evaluates the potential of future electron-positron colliders to detect leptophilic dark matter through effective field theory operators in mono-photon and mono-Z channels, providing sensitivity estimates for various operator types.

Contribution

It offers a comprehensive EFT analysis of leptophilic DM at future colliders, including beam polarization effects and sensitivity projections for different operator types.

Findings

Collider can probe DM up to 8.8 TeV cutoff scale for VA operators.

Sensitivity reaches up to 6.6 TeV for SP operators.

Provides the best sensitivity in the low-mass DM regime.

Abstract

We consider the possibility that dark matter (DM) only interacts with the Standard Model leptons, but not quarks at tree level, and analyze the future lepton collider prospects of such leptophilic DM in the monophoton and mono-$Z$ (both leptonic and hadronic) channels. Adopting a model-independent effective field theory framework, we consider all possible dimension-six operators of scalar-pseudoscalar (SP), vector-axial vector (VA), and tensor-axial tensor (TAT) types for a fermionic DM and derive the collider sensitivities on the effective cutoff scale $\Lambda$ as a function of the DM mass. As a concrete example, we take the beam configurations of the International Linear Collider with $\sqrt s=1$ TeV and $8$ ab$^{-1}$ integrated luminosity, including the effect of beam polarization, and show that it can probe leptophilic DM at $3\sigma$ level up to $\Lambda$ values of $6.6$, $8.8$, and $7.1$ TeV for the SP-, VA- and TAT-type operators, respectively. This is largely complementary to the direct and indirect searches for leptophilic DM and can potentially provide the best-ever sensitivity in the low-mass DM regime.