Semi-Visible Jets and Emerging Jets with Partial 3 Event Building

The nature of dark matter (DM) remains one of the biggest open questions in physics and has eluded astrophysical and cosmological scientists searching for indirect evidence of its existence. In recent years at the Large Hadron Collider (LHC), there has been an increase in efforts to explore the dark sector using LHC data. New studies explore the possibility of accessing the dark sector containing DM with unusual collider topologies. This report explores the recent DM model of dark sector jets with observable signatures called Semi-Visible Jets (SVJ), jets with some fraction of invisible DM particles, and Emerging Jets (EJ), jets with displaced vertices. Due to the constraint of recording information from every proton-proton (pp) collision event at the LHC, the ATLAS experiment at LHC uses a trigger and data acquisition (TDAQ) system that selects and sends interesting events to the data storage system while throwing away the rest. The challenge lies in situations where large backgrounds bury the interesting events and they are thrown out and not identified as signals by the trigger system. Partial Event Building (PEB) poses a solution by storing only part of the detector raw information, together with high level information. This leads to smaller event sizes and allows us to record larger datasets using the same storage space. This report conducts a preliminary feasibility study on triggering on the dark sector and leveraging PEB to search for dark sector models containing the unusual SVJs and EJs.