Physics Beyond Standard Model with the CMS Pixel Detector

University Of Puerto Rico Mayaguez, Mayaguez PR

Investigators

Abstract

The Standard Model of particle physics has been a successful theory, agreeing with decades of experimental observations involving weak, electromagnetic, and strong interactions. The discovery of the Higgs boson at the LHC was further confirmation of this success. However, the Standard Model remains an incomplete theory. This research focuses on probing the nature of the Universe at the smallest scales and its basic symmetries with the goal of understanding the stability of mass, the quantum nature of dark matter, and the relation of gravity to subatomic forces and extra spatial dimensions. This program is centered on the CMS experiment currently running at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. The precise measurements of the properties of the Higgs boson at the LHC could give insight into the nature of mass and the nature of electroweak symmetry breaking. The LHC might unveil lighter mass candidates for Supersymmetry, a theory that naturally explains electroweak symmetry breaking. The precise measurement of 'missing energy' could unveil signatures of many undiscovered particles, some of which could be candidates for Dark Matter. Missing energy could also account for the graviton escaping in extra-dimensions or for other exotic particles. The primary focus of this research is to exploit the capabilities of the newly installed CMS pixel detector to pursue searches for Supersymmetry. This new detector has an extra barrel and endcap layers, a reduced material profile, a new readout chip to minimize data losses due to high pile-up of LHC events, and an optimized detector layout for 4-pixel-hit coverage over the full CMS pseudorapidity range. These improvements translate to higher tracking efficiencies, lower fake-track rates, lower dead-time/data-loss, an extended lifetime of the detector, all leading to better muon identification, b-quark tagging, photon/electron identification, tau reconstruction, improved "particle flow" analysis, and missing energy reconstruction. An improved signal selection efficiency due to improved b-tagging and better missing energy estimation is central to this analysis program to discover Supersymmetry. This effort will also include activities in design and development of additional pixel detector upgrades while maintaining support of Pixel Detector Operations. This challenge of building, commissioning, and maintaining a state-of-the-art silicon detector provides workforce development opportunities in physics and engineering. The data analyses techniques and related algorithms, hardware instrumentation, grid computing, and big data science opportunities carried out in this award give students valuable experience and knowledge enabling them to pursue successful careers in academia or the private sector. The Quarknet outreach activities further foster collaboration with high school teachers, strengthening teaching and learning around the schools in Puerto Rico and motivating students to pursue STEM disciplines. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.