2017 Theses Doctoral

ATLAS Levels Up: Early Searches for Diboson Resonances in Semi-Hadronic Decay Channels at √ s = 13 TeV Center of Mass Energy

Alkire, Steven Patrick

Searches are made for narrow diboson resonances, 𝑍𝑍 and 𝑍𝑊, in the final states 𝓁𝓁𝑞𝑞 and 𝑣𝑣𝑞𝑞 at ATLAS, with (13.2±0.4) fb⁻¹ data collected from 𝑝𝑝-collisions with center of mass energy √s=13 TeV during 2015 and 2016, the first two years of Run 2 of the Large Hadron Collider. The hadronic decay products of the vector boson, 𝑉 → 𝑞𝑞, are reconstructed as jets in the electromagnetic and hadronic calorimeters. When the vector boson is sufficiently boosted the decay products are reconstructed as a single anti-kt R = 1.0 jet. Otherwise two anti-kt R = 0.4 jets are matched to identify the vector boson. The 𝑍 boson in its leptonic decay is identified by either reconstructing two electrons in the calorimeters, or opposite sign muons in the muon spectrometer. Limits on the production cross section for 3 benchmark signals, a heavy scalar, a spin-1 heavy vector triplet, and a spin-2 graviton are set in the mass range 300 GeV to 5000 GeV.