Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.775180
Title: Study of the neutral current interaction with a π⁰ in the final state in the ND280 detector of the T2K experiment
Author: Poplawska, Elzbieta
ISNI:       0000 0004 7962 3760
Awarding Body: Queen Mary, University of London
Current Institution: Queen Mary, University of London
Date of Award: 2015
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Abstract:
The Tokai to Kamioka (T2K) experiment is designed to detect νμ → νe appearance for the first time from accelerator generated neutrinos and measure neutrino oscillation parameters. The most intense accelerator muon neutrino beam ever built is produced at the J-PARC facility on the East coast of Japan, and sent 2.5° off-axis toward the Super-Kamiokande water Cherenkov detector. The main background for the recent appearance analysis comes from neutral current 1π⁰ interaction, accounting for 23% of the background events. In addition, the near detector (ND280) has been built to serve the requirement to provide high accuracy beam characteristics and background studies by measuring a number of neutrino cross-sections. In this thesis the NC1π⁰ channel studies at the near detector ND280 is performed. The studies aim to develop the NC1π⁰ event selection to single out the muon neutrino induced NC1π⁰ interactions in the PØ D (π⁰ Detector) sub-detector, where one π⁰ decay gamma converts in the PØ D and the second gamma converts in the PØ D-ECal (π⁰ Electromagnetic Calorimeter) sub-detector. The used data sample was collected during Runs II, III and IV, consisting of a total of 6:2 x 10²⁰ POT. Simulated events are generated with the NEUT MC to evaluate backgrounds and estimate the selection efficiency. The studies have been performed for the two PØ D configurations: filled with water and without water. The first approach to the usage of PØ D-ECal sub-detector in the NC1π⁰ channel studies showed that further improvements on the PØ D-ECal reconstruction and matching between the PØ D and PØ D-ECal is required. However, as a result of the performed analysis the total efficiency of 3.0% (4.0%) and purity of 17.7% (16.4%) is obtained for the PØ D filled with water (without water) configuration. Finally, after selection, 68 ± 8:2 (stat) (107 ± 10:3 (stat)) events passed all the requirements for the PØ D filled with (without) water. The developed selection lay the groundwork for the future measurement of the NC1π⁰ cross-section for the events induced by neutrinos interacting in the PØ D sub-detector and systematic errors evaluation, using larger data sets. As for now, the systematic uncertainties are a subject of a discussion in this thesis.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.775180  DOI: Not available
Keywords: T2K experiment
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