Portal Matter and Dark Sector Phenomenology at Colliders

If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of massive, likely $\gsim 1$ TeV, enabler portal matter (PM) particles that carry both dark and SM quantum numbers which will appear in vacuum polarization-like loop graphs. Such heavy states are only directly accessible at high energy colliders and apparently lie at mass scales beyond the direct kinematic reach of the ILC, CEPC and FCC-ee. A likely possibility is that these new particles are part of the 'next step' toward a UV-complete scenario describing both the SM and dark sector physics. A simple and straightforward example of such a scenario involving a non-abelian dark sector gauge group is employed in this work to demonstrate some of the range expected from this new physics. Here we present a broad survey of existing analyses designed to explore the nature of such PM states in a array of collider contexts, particularly at the LHC, and point out some of the future directions where additional work is obviously required in the hunt for new signatures as well as in model building directions.