Search for Evidence of Dark Matter Production in Monojet Events With the ATLAS Detector

Abstract

Dark Matter production at colliders may be evinced in topologies with an energetic jet recoiling against large missing transverse momentum, known as the “monojet” final state. This thesis presents a search for new physics in a sample of monojet events obtained from proton–proton collision data corresponding to an integrated luminosity of 3.2 fb−1 and center–of–mass energy √s = 13 TeV collected in 2015 with the ATLAS detector at the Large Hadron Collider. Monojet events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons. Several signal regions are constructed with sequential missing transverse momentum thresholds ranging from ETmiss > 250 GeV to ETmiss > 700 GeV. The number of events observed in data is consistent with Standard Model predictions. In the absence of an excess, limits are placed on the dark matter production cross section and compared to constraints from direct detection experiments and other collider searches.