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Title:Search for Diboson resonances in 8 tev and 13 tev proton-proton collisions at the large hadron collider with the atlas detector
Author(s):Atkinson, Markus
Director of Research:Neubauer, Mark
Doctoral Committee Chair(s):Thaler, Jon
Doctoral Committee Member(s):Fields, Brian; Eckstein, James
Department / Program:Physics
Discipline:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Diboson Resonance
ATLAS
CERN
FTK
Fast Tracker
8 TeV
13 TeV
Gravitons
Heavy Vector Triplet
Heavy Scalars
exclusion limits
Abstract:This thesis documents two searches for Diboson Resonances which were performed using data collected in 2012, 2015 and 2016 by the ATLAS detector at the Large Hadron Collider. Three benchmark models are tested: a model predicting the existence of a new heavy scalar singlet, a simplified model predicting a heavy vector-boson triplet (V ′), and a bulk Randall-Sundrum model with a heavy spin-2 graviton (G∗). Neither of these searches found evidence of any resonance, and exclusion limits are set on σ(pp → V ′) and σ(pp → G∗). For the 2012 ATLAS data, searches are performed for the G∗ and the W′. The sample corresponds to an integrated luminosity of 20.3 fb−1 proton-proton collisions with a center of mass energy √s = 8 TeV. This search looks for the decay channels G∗ → WW → lνjj and W′ → WZ → lνjj. No evidence for resonant diboson production is observed, and resonance masses below 760 GeV and 1490 GeV are excluded at 95% confidence level for the spin-2 Randall–Sundrum bulk graviton G∗ and the spin-1 extended gauge model W′ boson respectively. For the 2015 and 2016 ATLAS data, searches are performed for the G∗ and the V ′ and a heavy scalar. The sample corresponds to an integrated luminosity of 36.1 fb−1 proton-proton collisions with a center of mass energy √s = 13 TeV. This search looks for the decay channels G∗ → V V , scalar → V V and V ′ → V V/V H/dilepton. The V V and V H dibosons then decay into qqqq, ννqq, lνqq, llqq, lνlν, llνν, lνll, llll, qqbb, ννbb, lνbb, or llbb which are all combined (14 channels). No evidence for resonant diboson production is observed, and resonance masses below 2300 GeV are excluded at 95% confidence level for the spin-2 Randall–Sundrum bulk graviton G∗. Resonance masses below 5500 GeV and 4500 GeV are excluded at 95% confidence level for the heavy vector triplet in a weakly coupled scenario and a strongly coupled scenario respectively. No limits are extracted for the heavy scalar.
Issue Date:2019-07-05
Type:Text
URI:http://hdl.handle.net/2142/105786
Rights Information:© 2019 by Markus Atkinson. All rights reserved.
Date Available in IDEALS:2019-11-26
Date Deposited:2019-08


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