Natalie Gray Qualifying Exam

The Standard Model provides a fundamental description of the interactions between particles in our universe, but still leaves unresolved issues, which motivates the search for new particles. Axion-like particles (ALPs) are theoretically motivated particles that arise in extensions of the Standard Model and share similarities with the QCD axion, which in turn could solve the strong CP problem. This talk focuses on a specific analysis using the LAr calorimeter at the ATLAS detector to search for ALPs decaying into two photons and using Transformer models to improve signal identification and sensitivity. ATLAS is also continuing the search for particles beyond the Standard Model by upgrading its detector system in coordination with the high luminosity upgrades at the LHC. The University of Texas contributes to these upgrades through the design and testing of the COLUTA chip, a high resolution ADC made specifically for data readout. These upgrades will increase the collision rate in the detector enhancing the search for these rare particle events.