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

Atkinson, Markus

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https://hdl.handle.net/2142/105786 Copy

Description

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

Issue Date

2019-07-05

Director of Research (if dissertation) or Advisor (if thesis)

Neubauer, Mark

Doctoral Committee Chair(s)

Thaler, Jon

Committee Member(s)

• Fields, Brian
• Eckstein, James

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(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.

Graduation Semester

2019-08

Type of Resource

text

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

Copyright and License Information

© 2019 by Markus Atkinson. All rights reserved.

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