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Author(s)
| Liu, Jia (Chicago U., EFI ; Mainz U., Inst. Phys. ; U. Mainz, PRISMA) ; Wang, Lian-Tao (Chicago U., EFI ; Chicago U. ; Chicago U., KICP) ; Wang, Xiao-Ping (Mainz U., Inst. Phys. ; U. Mainz, PRISMA ; Argonne) ; Xue, Wei (CERN ; MIT, Cambridge, CTP) |
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Abstract
| 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 𝒪($10^{−6} − 10^{−8.5}$) for the Giga $Z$ and 𝒪($10^{−7.5} − 10^{−11}$) for the Tera $Z$, and they are compared with the projection for the high luminosity LHC. We demonstrate that future $Z$-factories can provide its unique and leading sensitivity, and highlight the complementarity with other experiments, including the indirect and direct dark matter search limits, and the existing collider limits. Future $Z$ factories will play a leading role to uncover the hidden sector of the universe in the future. |