LPC Graduate Scholar


Ryan Kim


Florida State University

What I will be working on:

As a 2023 LPC Graduate Scholar, I plan to continue and build on the projects I worked on as a 2022 LPC Graduate Scholar:

  1. I will continue my detector upgrade work with the HGCAL scintillator tile module assembly efforts at Fermilab. As we prepare for the beginning of HGCAL production in 2023, I will optimize performance of the pick-and-place machines used for tile module assembly to detect and place the scintillator tiles with accuracy of microns, working on both developing the software for the optical vision system and improving the machine hardware. Aside from the pick-and-place machines, I will work to converge on quality assurance procedures for tile modules, utilize Fermilab test beam periods to validate scintillator tiles, run tileboard test read outs, and develop quality control test stands for completed tile modules. Once production begins, I will ensure the pick-and-place machines are operated properly and perform quality control for the assembled tile modules.
  2. I also plan to continue my analysis work searching for heavy stable charged particles (HSCPs). HSCPs are particles theorized to have large masses, long lifetimes, and non-zero electric charge, with anomalous dE/dx in the tracker and delayed arrival in the muon system due to their relatively slow speed. I have been studying the complicated MET trigger behavior for this signal, which has increased in importance due to a recent excess reported by the ATLAS collaboration. I will work with the HSCP analysis group in collaboration with the LPC Long-Lived Particle group to arrive at a CMS publication for this signal. Then, I plan to build on this result by developing a machine learning (ML) strategy to improve mass reconstruction and background estimation. HSCPs lack dependable background simulations, so I plan to develop a robust data-driven background sample. I plan to carry out this ML-based analysis for Run 2 and early Run 3 data.

My role in CMS past and present:

I joined CMS in 2016 as an undergraduate student at the University of Notre Dame. I first worked on the HCAL Phase-1 upgrade hardware project, where I built components of optical decoder units and their calibration units. From 2017 to 2019 at Notre Dame and at the University of Rome Sapienza, I worked on a high-pT (> 200 GeV) photon identification project for the e/gamma physics object group. I developed optimized ID at various working points and wrote my senior thesis on the project in 2019. Since going to FSU for my graduate studies in 2019, I have worked on HSCP searches, where I have studied the complicated MET trigger for this signal and carried out some preliminary studies on DNNs and other ML classification methods to improve signal discrimination. As a 2022 LPC Graduate Scholar, I continued my work on the HSCP analysis and started working on HGCAL scintillator tile module assembly at Fermilab. I have worked on the pick-and-place machines used for tile module assembly, both developing the software for the optical vision system and improving the machine hardware.