{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/150460"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/150460","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Sterile neutrino searches at the Icecube Neutrino Observatory","abstract":"The IceCube Neutrino Observatory is capable of performing a unique search for sterile neutrinos through the exploitation of a matter enhanced resonant neutrino oscillation phenomena. As atmospheric muon neutrinos pass the dense material within the Earth, neutral current elastic forward scattering is predicted to induce a transition into a sterile state. This thesis presents two 3+1 sterile neutrino analyses by searching for spectral differences in the reconstructed energy and zenith direction of muon neutrino events, indicative of a transition into a sterile state. The first search probes the parameter space [delta]m²₄₁ and sin²(2[theta]₂₄) with relevant sensitivity to the global best fit region for a 3+1 sterile neutrino hypothesis. The second search performs a scan through sin²(2[theta]₂₄) and sin²([theta]₃₄) in the oscillation averaged out region of high-[delta]m²₄₁ ([theta]²₄₁ >~ 10 eV²). The analyses are performed using an improved event selection, which was found to extract 305,891 well reconstructed muon neutrino events with a sample purity above 99.9%, from eight years of IceCube data. Novel simulation techniques, along with updated calibration, and a re-assessment of the systematic uncertainties are also discussed. The first analysis finds a best fit sterile hypothesis point at [theta]²₄₁ = 4.47eV² and sin²([theta]₂₄ = 0.10, consistent with the no-sterile hypothesis at the 8% confidence level. The second analysis finds a best fit sterile hypothesis at sin²([theta]₃₄ = 0.40, sin²([theta]₃₄ =0.006, consistent with the null hypothesis at the 19% confidence level.","abstract_html":"The IceCube Neutrino Observatory is capable of performing a unique search for sterile neutrinos through the exploitation of a matter enhanced resonant neutrino oscillation phenomena. As atmospheric muon neutrinos pass the dense material within the Earth, neutral current elastic forward scattering is predicted to induce a transition into a sterile state. This thesis presents two 3+1 sterile neutrino analyses by searching for spectral differences in the reconstructed energy and zenith direction of muon neutrino events, indicative of a transition into a sterile state. The first search probes the parameter space [delta]m²₄₁ and sin²(2[theta]₂₄) with relevant sensitivity to the global best fit region for a 3+1 sterile neutrino hypothesis. The second search performs a scan through sin²(2[theta]₂₄) and sin²([theta]₃₄) in the oscillation averaged out region of high-[delta]m²₄₁ ([theta]²₄₁ >~ 10 eV²). The analyses are performed using an improved event selection, which was found to extract 305,891 well reconstructed muon neutrino events with a sample purity above 99.9%, from eight years of IceCube data. Novel simulation techniques, along with updated calibration, and a re-assessment of the systematic uncertainties are also discussed. The first analysis finds a best fit sterile hypothesis point at [theta]²₄₁ = 4.47eV² and sin²([theta]₂₄ = 0.10, consistent with the no-sterile hypothesis at the 8% confidence level. The second analysis finds a best fit sterile hypothesis at sin²([theta]₃₄ = 0.40, sin²([theta]₃₄ =0.006, consistent with the null hypothesis at the 19% confidence level.","abstract_has_math":false,"creators":["Axani, Spencer Nicholas Gaelan, author."],"institution":"Massachusetts Institute of Technology","degree_name":"Doctoral","degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Physics","school":null,"contributors":[],"advisors":["Conrad, Janet M."],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020","date_published":"2020","updated_at":"2026-07-22T22:21:22Z","subjects":["Physics."],"languages":["eng"],"rights":["MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1721.1/150460","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Conrad, Janet M."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Department of Physics"]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. 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Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1721.1/150460"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: Sc. D., Massachusetts Institute of Technology, Department of Physics, 2020","\"The following pages, 92-94, were not included in the original document submitted to the MIT Libraries. This is the most complete copy available\"--Disclaimer page. Cataloged from PDF version of thesis. Supervised by Janet M. Conrad.","Includes bibliographical references (pages 217-239)."]},{"key":"dc:description.abstract","label":"Abstract","values":["The IceCube Neutrino Observatory is capable of performing a unique search for sterile neutrinos through the exploitation of a matter enhanced resonant neutrino oscillation phenomena. As atmospheric muon neutrinos pass the dense material within the Earth, neutral current elastic forward scattering is predicted to induce a transition into a sterile state. This thesis presents two 3+1 sterile neutrino analyses by searching for spectral differences in the reconstructed energy and zenith direction of muon neutrino events, indicative of a transition into a sterile state. The first search probes the parameter space [delta]m²₄₁ and sin²(2[theta]₂₄) with relevant sensitivity to the global best fit region for a 3+1 sterile neutrino hypothesis. The second search performs a scan through sin²(2[theta]₂₄) and sin²([theta]₃₄) in the oscillation averaged out region of high-[delta]m²₄₁ ([theta]²₄₁ >~ 10 eV²). The analyses are performed using an improved event selection, which was found to extract 305,891 well reconstructed muon neutrino events with a sample purity above 99.9%, from eight years of IceCube data. Novel simulation techniques, along with updated calibration, and a re-assessment of the systematic uncertainties are also discussed. The first analysis finds a best fit sterile hypothesis point at [theta]²₄₁ = 4.47eV² and sin²([theta]₂₄ = 0.10, consistent with the no-sterile hypothesis at the 8% confidence level. The second analysis finds a best fit sterile hypothesis at sin²([theta]₃₄ = 0.40, sin²([theta]₃₄ =0.006, consistent with the null hypothesis at the 19% confidence level."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Sc. D."]},{"key":"dc:title","label":"Title","values":["Sterile neutrino searches at the Icecube Neutrino Observatory"]}]}],"canonical_facts":{"dc:contributor.advisor":["Conrad, Janet M."],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Physics"],"dc:contributor.other":["Massachusetts Institute of Technology. Department of Physics."],"dc:creator":["Axani, Spencer Nicholas Gaelan, author."],"dc:date.accessioned":["2023-04-07T16:54:30Z"],"dc:date.available":["2023-04-07T16:54:30Z"],"dc:date.issued":["2020"],"dc:description":["Thesis: Sc. D., Massachusetts Institute of Technology, Department of Physics, 2020","\"The following pages, 92-94, were not included in the original document submitted to the MIT Libraries. This is the most complete copy available\"--Disclaimer page. Cataloged from PDF version of thesis. Supervised by Janet M. Conrad.","Includes bibliographical references (pages 217-239)."],"dc:description.abstract":["The IceCube Neutrino Observatory is capable of performing a unique search for sterile neutrinos through the exploitation of a matter enhanced resonant neutrino oscillation phenomena. As atmospheric muon neutrinos pass the dense material within the Earth, neutral current elastic forward scattering is predicted to induce a transition into a sterile state. This thesis presents two 3+1 sterile neutrino analyses by searching for spectral differences in the reconstructed energy and zenith direction of muon neutrino events, indicative of a transition into a sterile state. The first search probes the parameter space [delta]m²₄₁ and sin²(2[theta]₂₄) with relevant sensitivity to the global best fit region for a 3+1 sterile neutrino hypothesis. The second search performs a scan through sin²(2[theta]₂₄) and sin²([theta]₃₄) in the oscillation averaged out region of high-[delta]m²₄₁ ([theta]²₄₁ >~ 10 eV²). The analyses are performed using an improved event selection, which was found to extract 305,891 well reconstructed muon neutrino events with a sample purity above 99.9%, from eight years of IceCube data. Novel simulation techniques, along with updated calibration, and a re-assessment of the systematic uncertainties are also discussed. The first analysis finds a best fit sterile hypothesis point at [theta]²₄₁ = 4.47eV² and sin²([theta]₂₄ = 0.10, consistent with the no-sterile hypothesis at the 8% confidence level. The second analysis finds a best fit sterile hypothesis at sin²([theta]₃₄ = 0.40, sin²([theta]₃₄ =0.006, consistent with the null hypothesis at the 19% confidence level."],"dc:description.degree":["Sc. D."],"dc:identifier.uri":["https://hdl.handle.net/1721.1/150460"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Physics."],"dc:title":["Sterile neutrino searches at the Icecube Neutrino Observatory"],"dc:type":["Academic theses.","Thesis"],"thesis:degree_name":["Doctoral"]},"updated_at":"2026-07-22T22:21:22Z"}