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%0 Thesis
%A Soldin, Philipp
%T Improvements in the measurement of the neutrino mixing angle θ<sub>13</sub> with the Double Chooz experiment
%I RWTH Aachen University
%V Dissertation
%C Aachen
%M RWTH-2023-09118
%P 1 Online-Ressource : Illustrationen, Diagramme
%D 2023
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University
%Z Dissertation, RWTH Aachen University, 2023
%X Double Chooz is a reactor neutrino disappearance experiment that was operating between 2011 until the beginning of 2018. Its primary purpose was the precise measurement of the neutrino mixing angle θ<sub>13</sub>, or more precisely, the neutrino mixing amplitude sin<sup>2</sup>(2θ<sub>13</sub>). The experimental setup consisted of two identical liquid scintillator detectors at average baselines of about 400m and 1km to two nuclear reactor cores in Chooz, France. The neutrinos were detected by measuring the inverse beta decay (IBD) signature, which consists of prompt positron annihilation and delayed neutron capture signals. Using the rate and spectral energy shape of the measured neutrinos and taking into account all relevant background contributions, the neutrino mixing amplitude sin<sup>2</sup>(2θ<sub>13</sub>) can be obtained. This thesis describes the implementation of a software framework that realizes all these aspects efficiently and performantly in a Poisson -based Likelihood fit. The analysis is checked thoroughly for self-consistency and is cross-validated to ensure an unbiased reconstruction result. Using a spectral energy modeling technique to incorporate deviations from the initially assumed reactor neutrino energy spectrum allows for an adaptation and extraction of these deviations across multiple data sets. The presented analysis gives an estimate for the neutrino mixing amplitude of sin<sup>2</sup>(2θ<sub>13</sub>) = 0.1036 <sup>+0.0117</sup><sub>−0.0118</sub>. It is also shown how the reactor neutrino energy spectra can be efficiently split to incorporate the runtime of each nuclear reactor. This change allows an improved estimate of sin<sup>2</sup>(2θ<sub>13</sub>)<sub>\textReactor Split</sub> = 0.0960<sub>−0.0105</sub><sup>+0.0102</sup> with a 13% improvement uncertainty. All the fit results are compatible with previous results from the Double Chooz collaboration.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2023-09118
%U https://publications.rwth-aachen.de/record/969334