Searching for a Strongly Coupled Dark Sector with the CMS Detector

Searches for long-lived particles (LLPs), especially those associated with a dark matter (DM) candidate, have become a major focus of the Compact Muon Solenoid (CMS) physics program. During Run 2 of the Large Hadron Collider (LHC) at CERN, CMS became the first experiment to publish a search for a strongly coupled dark sector which contains a composite dark matter particle. This model contains a striking phenomenological signature consisting of emerging jets, whose tracks seem to appear not from the proton-proton collision vertex, but from multiple vertices within the CMS tracking detector. I will discuss this search as well the updated and ongoing version of the search. I will also discuss ongoing work to upgrade the CMS level-1 hardware trigger in order to prepare this system for the High Luminosity LHC (HL-LHC) with its unprecedented numbers of simultaneous proton-proton collisions. I will focus on the parts of the system which reconstruct the trajectories of charged particles, how these tracks are used by the downstream trigger systems, and how these upgrades will enable future dark sector searches at CMS.