Abstract:
T2K is a long-baseline neutrino experiment in Japan that has been operated for over 10 years with recently upgraded neutrino beam and near detector suits.. Neutrino oscillation parameters are measured through neutrino event distributions at the near and far detectors. The far detector has signal events contributed from charged-current (CC) interactions, produces electron-like or muon-like Cherenkov rings in water. The 1-ring neutral current (NC) pi0 events is a major background in the oscillated electron neutrino events, which can affect the sensitivity of measuring dCP and Theta13. Current selection has shown a fraction of CCQE electron-like events miss-reconstructed as NC1pi0 interactions in the oscillation analysis, which can be recovered by including the new 1-ring NC1pi0 sample. A high purity (>76%) and efficiency (>72%) 2-ring NC1pi0 sample selection is also available to help understand pi0 interaction cross sections to control the NC1pi0 events in the 1-ring NC1pi0 sample. Studies are performed to understand how to adapt these new sample properly in an upcoming oscillation analysis.
On the other hand, improvements in measuring the oscillated nue events was investigated by developing additional constraints to electron neutrino-nucleus interaction cross sections. The Intermediate Water Cherenkov Detector (IWCD), containing 500t of water, is a proposed near detector for the future Hyper-Kamiokande experiment, located 750m from the beam production target. The large detector volume with excellent electron identification power will provide high statistics of electron neutrino and antineutrino samples, while the off-axis angle flux dependence from vertical movements allows different spectra of the true neutrino energy dominated by various types of neutrino interactions to be observed.
Biography:
Tailin Zhu is a PhD student at Imperial College London. Her work is focused on improving the oscillation analysis for the long baseline neutrino experiments. She started from the simulation, calibration and DAQ maintenance work for the neutrino beam profile monitoring at J-PARC. At the mean time, she gradually moved onto neutrino oscillation analysis for Hyper-K and T2K by implementing new features on the sample selection and systematic parameters to the analysis. She is now approaching the final thesis timeline by accumulating her analysis towards an improvement on the neutrino oscillation sensitivity for T2K.
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