University of Illinois Urbana-Champaign

Searches for supersymmetric particles and ATLAS track triggers

Cao, Yumeng

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https://hdl.handle.net/2142/130025

Description

Title
Searches for supersymmetric particles and ATLAS track triggers
Author(s)
Cao, Yumeng
Issue Date
2025-07-07
Director of Research (if dissertation) or Advisor (if thesis)
Hooberman, Benjamin H
Doctoral Committee Chair(s)
Sickles, Anne M
Committee Member(s)
  • Cooper, Stephen L
  • Kahn, Yonatan F
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Supersymmetry
  • ATLAS experiment
  • Large Hadron Collider
  • displaced leptons
  • track trigger
  • Fast TracKer (FTK)
  • Hardware Track Triggers (HTT)
  • Run-2
  • Run-3
  • particle physics
Abstract
The Standard Model of particle physics has profoundly shaped our understanding of the fundamental forces and constituents of the universe. Despite its success, the model's inability to incorporate gravitational interactions and dark matter indicates significant gaps in our understanding of the universe's underlying structure. The quest for a more encompassing theory has led to the exploration of Supersymmetry (SUSY), a promising extension of the Standard Model that hypothesizes the existence of superpartners for every known particle. The discovery of SUSY particles would not only revolutionize our understanding of the fundamental particles but also provide critical insights into the dark sector of the universe. The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is at the forefront of this search. Operating at unprecedented energies, the LHC offers a unique window into physics beyond the Standard Model. Within this global endeavor, the ATLAS collaboration plays a pivotal role by probing new physics through its versatile detector system designed to capture a wide array of particle interactions. My PhD research is conducted within the framework of the ATLAS collaboration, focusing on the experimental search for SUSY particles and enhancing the capabilities of the ATLAS detector through technological innovations. This dissertation presents detailed accounts of my participation in searches for SUSY in 2 lepton and jets final states during the LHC Run-2 and in displaced lepton scenarios in Run-3. These searches target events where SUSY particles decay into final states that include leptons and jets, exploiting unique signatures that differentiate them from Standard Model backgrounds. The complexity of these searches requires the development and application of sophisticated data analysis techniques. Parallel to these experimental searches, this dissertation also details my contributions to the development of the ATLAS track trigger system. The enhancements to this system are critical for the detector's ability to manage and analyze data at the high event rates encountered in LHC Run-3 and the upcoming Run-4. Improvements in the track trigger system directly translate to better real-time event selection capabilities, which are essential for isolating rare physics events from the vast datasets generated by the collider. The methodologies employed in this research combine cutting-edge particle physics analysis techniques with state-of-the-art simulation tools and detector technologies. This comprehensive approach not only advances the search for SUSY but also contributes to the broader field of particle physics by enhancing the experimental techniques used in high-energy physics research. The results of these searches have significant implications for the field of particle physics. They either set stringent limits on SUSY theories or could potentially lead to discoveries that would necessitate a reevaluation of our current understanding of the physical universe. As the LHC continues to operate at higher luminosities and energies, the research documented in this dissertation will serve as a cornerstone for future explorations in the field.
Graduation Semester
2025-08
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/130025
Copyright and License Information
Copyright 2025 Yumeng Cao

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