Preliminary studies toward Trigger-Level Analysis with Photons in ATLAS

Abstract: The Trigger-Level Analysis is a strategy for data analysis that enables recording larger amounts of events at the ATLAS experiment than the typical method of reconstructing events offline. This is done by only recording partial information about the event, and using that for analysis. As more events are analysed with this method it can be used to put lower energy constraints on the events that are analysed, meaning that events which would otherwise not pass trigger cuts can be stored. This work considers a model of dark matter in which dark matter can interact with ordinary matter through a mediator particle. The mediator is of a mass range where it decays into two jets that are unlikely to have enough energy to pass the trigger cuts at a significant rate. A Trigger-Level Analysis could potentially probe this region of mediator masses. The work gives a preliminary look into the possibility of using photons for this, in association with dijet events. This shows that photons could potentially be used, as they display a similar performance to jets even without calibration, but will need further studies and methods to remove fake photons at the trigger level.