LAUSR

Dark axion portal connects an axion-like-particle (ALP), which can be the QCD axion, with the SM by the coupling to a photon and a dark photon, leading to a rich and distinct phenomenology related to dark matter, astrophysics, and cosmology. We note that due to the gauge invariance, the Z boson-dark photon-ALP coupling should also be generated with sizable strength, and we study its phenomenological consequences at Z boson factories: LEP, FCC-ee, and forward physics detectors at the LHC and FPF@FCC - FASER and MATHUSLA. Due to the large number of Z bosons produced, DAP particles can be efficiently produced and detected by semi-visible displaced decays of the heavier DS species to γ+inv. or f+f−+inv., and via missing energy signature with zero or one photon. Because of the complementarity of the two approaches, we find great prospects in exploring both short and long-lived lifetime regimes of DAP, especially when the heavier dark species has mass above 0.1 GeV.