This title appears in the Scientific Report :
2022
Please use the identifier:
http://hdl.handle.net/2128/32972 in citations.
Please use the identifier: http://dx.doi.org/10.18154/RWTH-2022-06349 in citations.
Geoneutrinos and Solar neutrinos with the Borexino experiment
Geoneutrinos and Solar neutrinos with the Borexino experiment
The work presented in this dissertation is centered around the recent geoneutrino and solar neutrino measurements carried out with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. The improved geoneutrino measurement includes a substantial increase in the precision and the rejecti...
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Personal Name(s): | Kumaran, Sindhujha (Corresponding author) |
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Ludhova, Livia (Thesis advisor) / Stahl, A. (Thesis advisor) | |
Contributing Institute: |
Experimentelle Hadrondynamik; IKP-2 |
Imprint: |
RWTH Aachen University
2022
|
Physical Description: |
pages 1 Online-Ressource : Illustrationen, Diagramme |
Dissertation Note: |
Dissertation, RWTH Aachen, 2022 |
DOI: |
10.18154/RWTH-2022-06349 |
Document Type: |
Dissertation / PhD Thesis |
Research Program: |
Cosmic Matter in the Laboratory |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.18154/RWTH-2022-06349 in citations.
The work presented in this dissertation is centered around the recent geoneutrino and solar neutrino measurements carried out with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. The improved geoneutrino measurement includes a substantial increase in the precision and the rejection of the no-mantle signal with a very high significance. These results have been achieved through my different contributions, such as the optimisation of the event selection cuts, evaluation of the several non-antineutrino backgrounds, estimation of the systematic uncertainties, as well as the refinement and execution of the final spectral fits. The results have been also validated using sensitivity studies. A comprehensive overview of this analysis and the final results have been published by the Borexino collaboration in Physical Review D and this article has been co-written by me. The latest solar neutrino measurements of Borexino include the first experimental evidence of the Carbon-Nitrogen-Oxygen (CNO) cycle in the Sun and the first directional measurement of sub-MeV solar neutrinos. For the analysis of CNO neutrinos, the primary contribution presented in this thesis is the estimation of the upper limit on the Bi-210 background rate, which is crucial for the observation of the rare CNO solar neutrinos. Furthermore, the CNO rate has been obtained through a multivariate spectral fit, along with an assessment of the systematic uncertainty arising from the fit parameters. These results containing my contributions have been published by the Borexino collaboration in Nature. This dissertation also presents the upgraded Bi-210 upper limit, as well as the multivariate fit results using the newly acquired, highly stable, and final data set of Borexino. Finally, I present my work regarding the directional measurement which comprises calibration of the Cherenkov light in Borexino Monte-Carlo utilising gamma sources, optimisation of the event selection, validation and improvement of the analysis strategy, estimation of the systematic uncertainties, as well as the execution of the final fits to obtain the solar neutrino signal and the Be-7 solar neutrino rate. This measurement by the Borexino collaboration has been accepted for a joint-publication in Physical Review Letters and Physical Review D and these articles have been co-written by me. |