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- Title
- DESIGN OF A COVARIANCE MATRIX FITTER TO MEASURE THE ELECTRON ANTINEUTRINO OSCILLATION PARAMETERS USING NEUTRON HYDROGEN CAPTURE AT THE DAYA BAY EXPERIMENT
- Creator
- De Arcos Rodr´iguez, Jos´e Fernando
- Date
- 2015, 2015-12
- Description
-
The Daya Bay experiment provided the first precision measurement of the third mixing angle of the Pontecorvo-Maki-Nakagawa-Sakata matrix (✓13)...
Show moreThe Daya Bay experiment provided the first precision measurement of the third mixing angle of the Pontecorvo-Maki-Nakagawa-Sakata matrix (✓13) using six detectors to determine the relative rates of correlated signals generated from gadolinium neutron capture and positron-electron annihilation gammas in the inverse beta decay process. An additional correlated hydrogen neutron capture signal is produced in the Daya Bay detectors. Its analysis has the potential of producing an independent measurement of the electron antineutrino oscillation parameters. In this thesis a fitter has been designed to measure ✓13 and the squared mass di↵erence (#m2 ee) using the shape information of the hydrogen neutron capture signal generated in the Daya Bay experiment detectors. The main challenges of the hydrogen capture signal are the high accidental background rates in the lower energy region, and hydrogen’s neutron capture cross-section being much lower than gadolinium’s. In order to have a significant signal, we had to use more aggressive selection cuts than those applied in the gadolinium neutron capture analysis, and the fiducial volume was expanded by including the gadolinium-free gamma catcher region. Both background and detector systematic uncertainties studies have been repeated for the new hydrogen signal conditions. The results of these studies have been used to produce the corresponding covariance matrices that account for the uncertainties in a covariance matrix fitter. The fitter is customizable, i.e., energy binning, antineutrino detector configuration, data periods to be fitted, reactor periods, detector response matrices and predictions can be configured using a graphical user interface, providing versatility for further research. The fitter performance has been tested in the two dimensional parameter space S ⇥ D, where S = !sin2(2✓13) 2 [0, 0.002, 0.004, ...0.2]} and D = {#m2 ee 2 [0.0015, 0.00152, 0.00154...0.0035]}, using nominal and statistically fluctuated antineutrino spectrum predictions.
Ph.D. in Physics, December 2015
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- Title
- Analysis of the Prompt Energy and Ab Initio Spectra with the Daya Bay Reactor Neutrino Experiment
- Creator
- Asimacopoulos, Leia
- Date
- 2019
- Description
-
Theorized in the 1930s and discovered in the 1950s, neutrinos have puzzled physicists for decades. One method of studying neutrinos and their...
Show moreTheorized in the 1930s and discovered in the 1950s, neutrinos have puzzled physicists for decades. One method of studying neutrinos and their properties is measuring energy spectra produced by interactions of antineutrinos which come from beta decays of isotopes in nuclear reactors. With precise enough detectors, the antineutrino spectra of specific isotopes, also referred to as fine structure, may be observed. In this study, theoretical models of antineutrino energy spectra are compared with measured energy spectra from the Daya Bay Reactor Neutrino Experiment to test if the resolution of Daya Bay's detectors is precise enough to measure fine structure.
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