Authors:	Lohfink, Elisa
Title:	Testing nonstandard neutrino interaction parameters with IceCube-DeepCore
Online publication date:	27-Jul-2023
Year of first publication:	2023
Language:	english
Abstract:	Currently, the clearest evidence for physics beyond the Standard Model is provided by observations that indicate non-zero neutrino masses. Numerous theories on how these masses are generated give rise to additional non-standard interactions (NSI) of neutrinos with quarks and charged leptons. Atmospheric neutrinos provide a sensitive probe for the neutrino flavor transitions resulting from the type of NSI investigated in this work. These comprise neutral current forward scattering of neutrinos of all flavors on first generation charged fermions in Earth matter. In order to maximize model independence, the NSI are parametrized using five effective coupling strengths. In the IceCube-DeepCore detector, atmospheric neutrinos are detected indirectly via Cherenkov photons produced within the Antarctic glacier. The range of angles under which neutrinos enter the detector translates into propagation baselines of O(1 − 10000 )km. The data sample used in the presented analysis includes 9.3 years of DeepCore data, covering a neutrino energy range of 5 to 100 GeV. Accuracy and performance of event property reconstruction from observed photons are a crucial factor for the analysis outcome. Therefore, this work includes a thorough study of the potential and shortcomings of likelihood based DeepCore event reconstruction algorithms. The presented analysis relies on comparing binned observed event counts to simulation that is generated at different hypotheses. These include the individually considered NSI parameters as well as 17 nuisance parameters. In order to find the hypothesis that best describes the observation, the optimum of a test statistic is determined using a customized minimization strategy. The final analysis setup yields sensitivities to four effective NSI couplings that are competitive compared with existing results.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-9288
URN:	urn:nbn:de:hebis:77-openscience-346ca53b-8e9c-4dd3-8d3e-16c97b4ec8d91
Version:	Original work
Publication type:	Dissertation
License:	CC BY-ND
Information on rights of use:	https://creativecommons.org/licenses/by-nd/4.0/
Extent:	xviii, 225 Seiten ; Illustrationen, Diagramme
Appears in collections:	JGU-Publikationen