The ATLAS experiment at the Large Hadron Collider (LHC) has a broad and systematic search program for dark matter. Many models of dark matter predict a new particle that mediates the interaction between Standard Model particles and dark matter. If this mediator can be produced by colliding protons at the LHC, then it should also decay to components of the proton, producing a dijet resonance signature in the detector.
With the unprecedented high luminosity delivered by the LHC, detector readout and data storage limitations restrict conventional dijet searches to resonance masses of about 1 TeV or higher. In order to extend the search range to lower masses on the order of 100 GeV and probe weaker couplings, the ATLAS experiment employs a range of novel trigger and analysis strategies. One of these is the trigger-level analysis (TLA), which records only trigger-level jet objects instead of the full detector information. This strategy of using only partial event information permits the use of lower jet trigger thresholds and increased recording rates with minimal impact on the total output bandwidth.
This talk will present the most recent results from the Run 2 djiet TLA search using these techniques and discuss extensions of the trigger-level analysis strategy.