Search for Diboson resonances in 8 tev and 13 tev proton-proton collisions at the large hadron collider with the atlas detector

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Atkinson, Markus

Contributors dc:contributor

• Neubauer, Mark
• Thaler, Jon
• Fields, Brian
• Eckstein, James

• Fast Tracker
• 8 TeV
• Diboson Resonance
• ATLAS
• CERN
• FTK
• 13 TeV
• Gravitons
• Heavy Vector Triplet
• Heavy Scalars
• exclusion limits

Statement dc:rights

• © 2019 by Markus Atkinson. All rights reserved.

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/105786

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/105786