UROP Proceedings 2022-23

School of Science Department of Physics 63 Investigation of CP Symmetry in Neutrino Oscillation Supervisor: LUK, Kam Biu / PHYS Student: LAI, Chun Kit / PHYS Course: UROP1000, Summer Neutrino oscillation is a phenomenon describing the inter-conversion between neutrino flavors. As neutrinos are typically known for only participating in weak interactions which violates CP-symmetry, whether this phenomenon also breaks the symmetry is also of interest. This project attempts to find the CP-violating phase through simulation of muon-electron neutrino conversion, finding its probability which has dependence on such phase. This report discusses the expected dependence of the probability on the CPphase based on how neutrino oscillation is mathematically described. A plot on this probability as a function of the neutrino energy and how such dependence is affected by the CP-violating phase is given. Investigation of CP Symmetry in Neutrino Oscillation Supervisor: LUK, Kam Biu / PHYS Student: XU, Sihong / PHYS Course: UROP2100, Summer The investigation of neutrino interactions is deemed to be of great significance in the study of CP violation in neutrino experiments. A (anti)neutrino-nucleon interaction can be classified into elastic scattering, quasielastic scattering (QE), inelastic scattering (IE) and deep inelastic scattering (DIS), combined with a neutral-current (NC) or a charged-current (CC) reaction. Based on this point, in this article (anti)electron neutrino-carbon interactions are simulated using GENIE, with beam energies ranging from 0.1 GeV to 0.5 GeV. The focus of this study is on the analysis of the momentum and energy distributions, as well as the multiplicity of the final-state particles, such as the final-state nucleons, nuclei, and leptons. Both similarities and differences are observed in the neutrino and antineutrino reactions, and qualitative explanations of the phenomena are provided. Search for Light Dark Matter with Positronium Supervisor: LUK, Kam Biu / PHYS Student: AU, Kei Yin Eltis / PHYS Course: UROP1100, Fall UROP2100, Spring Dark matter, which is a type of material that by definition is weakly interact with light. In our group, we hope to design and construct an experiment for searching for positronium decaying into invisible light dark matter. This is the second report for this project, which we focused on discussing how to stop the beta plus particle by simulating the interaction of beta particle inside different material by Geant4.