# Dijet resonance searches for dark matter mediators using the ATLAS detector

Eric Edward Corrigan

Research output: ThesisDoctoral Thesis (monograph)

## Abstract

Dark matter is abundant in the universe, yet its composition and nature are unknown. If dark matter consists of new particles with nonzero interactions with Standard Model particles, it could be produced and detected or inferred by collider experiments. This thesis describes searches for dark matter models with new spin-1 force mediators coupling dark matter to quarks, using the ATLAS detector at the LHC. The studies target processes where a mediator is resonantly produced and decays back into two quarks, leaving two collimated jets of particles in the detector, and use $\sqrt{s} = 13 \TeV$ data recorded by ATLAS between 2015 and 2017. No evidence for new physics was seen, and exclusion limits were set on benchmark models. Additionally, we describe how such limits can be reinterpreted in the contexts of other models to provide further constraints.

In order to conduct these searches, well-calibrated jets are needed, as well as good understanding of detector performance. This thesis also describes several tools and studies aimed at improving the jet physics performance of ATLAS. In particular, methods for studying the jet energy calibration and resolution are presented.
Original language English Doctor Particle Physics Doglioni, Caterina, SupervisorÅkesson, Torsten, Assistant supervisorLönnblad, Leif, Assistant supervisor European Research Council (ERC) 2021 Jun 14 Lund Lund University (Media-Tryck) 978-91-7895-911-2 978-91-7895-912-9 Published - 2021 May 17

### Bibliographical note

Defence details
Date: 2021-06-14
Time: 13:15
Place: Lund University. Join via zoom: https://lu-se.zoom.us/j/61854872462
External reviewer(s)
Name: Bose, Tulika
Title: Professor
Affiliation: University of Wisconsin
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## Subject classification (UKÄ)

• Subatomic Physics

## Keywords

• particle physics
• dark matter
• jets
• dijet resonance
• ATLAS
• LHC
• Fysicumarkivet A:2021:Corrigan

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