|Ph.D Student||Gozani Eitan|
|Subject||A Search for Dark Matter using the ATLAS Detector|
|Department||Department of Physics||Supervisor||Professor Yoram Rozen|
|Full Thesis text|
The Dark Matter problem is a long-standing discrepancy between the measured gravitational force and luminous mass, observed in astrophysical systems covering many length scales. One solution to this discrepancy predicts the existence of new, Weakly-Interacting, Massive Particles (WIMP). This work reports the findings of a search for WIMP pair production events with associated 3rd generation quarks in proton-proton collisions at the Large Hadron Collider. The study was performed using the ATLAS detector, and is based on a data set with a total integrated luminosity of L=36.1 fb-1. It relies on the precise definition and reconstruction of hadronic jets, leptons, and the transverse momentum imbalance. The search was conducted using five different event classifiers that were optimised for Dark Matter discovery and cover the various final signatures of the associated production process. No significant excess of observed events above the expected Standard Model background was found. Correspondingly, upper limits on the WIMP production cross section were set. Additionally, the limits converted to WIMP-nucleon scattering cross section to be compared with direct detection experiments. The analysis set the most stringent limits to date for the specific models used to characterise the WIMP and its interactions.