Search for invisible dark photon in $\gamma e$ scattering at future lepton colliders

TL;DR

This paper investigates the potential to detect invisible dark photons produced in gamma-electron scattering at future lepton colliders, analyzing missing energy signatures across a broad mass range and setting exclusion limits.

Contribution

It is the first study to examine dark photon production via gamma-electron scattering at future colliders, considering both unpolarized and polarized collisions and invisible decay modes.

Findings

Excluded regions in the kinetic mixing vs. mass plane at 95% C.L.

Analysis of missing energy distributions for different dark photon masses.

Feasibility of detecting invisible dark photons at future colliders.

Abstract

For the first time, the production of a massive dark photon (DP) in the $\gamma e^-$ scattering at the future lepton colliders ILC, CLIC, and CEPC is examined. The invisible decay mode of the DP is addressed. We have studied both the unpolarized scattering and the collision of the Compton backscattered photons with the polarized electron. The missing energy distributions are shown. We have considered the wide range 10 GeV -- 1000 GeV of the DP mass $m_{A'}$. The excluded regions at the 95\% C.L. in the plane $(\varepsilon, m_{A'})$, where $\varepsilon$ is the kinetic mixing parameter, are obtained.