Exposing Dark Sector with Future Z-Factories

Understand

We investigate the prospects of searching dark sector models via exotic Z-boson decay at future $e^+ e^-$ colliders with Giga Z and Tera Z options.

• Four general categories of dark sector models: Higgs portal dark matter, vector portal dark matter, inelastic dark matter and axion-like particles, are considered.
• Focusing on channels motivated by the dark sector models, we carry out a model independent study of the sensitivities of Z-factories in probing exotic decays.
• The limits on branching ratios of the exotic Z decay are typically $\mathcal{O} (10^{-6} - 10^{-8.5}) $ for the Giga Z and $\mathcal{O} (10^{-7.5} - 10^{-11})$ for the Tera Z, and they are compared with the projection for the high luminosity LHC.