Search for Diboson Resonances in the Fully Hadronic Final State Using Jet Substructure Techniques in 8 and 13 TeV Proton-Proton Collisions with the ATLAS Detector

Abstract

In this thesis, searches for narrow resonances decaying into pairs of vector bosons (WW, WZ and ZZ) are presented. The searches are performed using 20.3 fb-1 and 3.2 fb-1 of proton-proton collision data collected with the ATLAS experiment at the LHC at centre-of-mass energies of 8 TeV and 13 TeV, respectively. Events are selected in the fully hadronic final state, characterised by two large-radius jets. Requirements on the jet mass and substructure variables are imposed to select large-radius jets that are compatible with the hadronic decay of highly boosted W or Z bosons. In the absence of a significant deviation from the background prediction, exclusion limits at 95% confidence level are set on the production cross-section times branching ratio for three benchmark models: a bulk Randall-Sundrum model, an extended gauge model and a heavy vector triplet model.