Searches for dark matter mediators with dijet final states in pp collisions at √s = 13 TeV with the ATLAS detector at the LHC

The ATLAS experiment at the Large Hadron Collider (LHC) has a rich programme of searches for dark matter, encompassing a wide range of models and signatures. Many models of dark matter feature a new particle that mediates the interaction between Standard Model particles and dark matter; this mediator particle could decay to quarks and gluons, 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 searches for dijet resonances to 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. These include searches for dijet resonances produced in association with a photon or jet from initial-state radiation (dijet+ISR), and the trigger-level analysis (TLA), which records only trigger-level jet objects instead of the full detector information, thus permitting 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 dijet searches using these techniques.