TY - BOOK

T1 - A Search for Tau Neutrino Appearance with IceCube-DeepCore

AU - Larson, Michael James

PY - 2018

Y1 - 2018

N2 - Neutrino have been known to oscillate between the three flavors since the firstdiscoveries two decades ago. Over that time, our knowledge of the parameters whichgovern these oscillations has improved significantly. The largest remaining uncertaintiesin the measurement of neutrino oscillations are those that govern the tau neutrino. In thisthesis, a direct measurement of tau neutrino oscillations is performed with the IceCubeNeutrino Observatory located in the ice deep beneath the South Pole.The measurement of atmospheric tau neutrino appearance requires a precise understandingof backgrounds. In order to perform the measurement, improvements to themodeling of the detector noise have been performed, reducing the uncertainties in thenoise model used in IceCube significantly. Additional improvements to the simulationefficiency investigated during this thesis reduce the computational requirements of atmosphericmuon background events by more than three orders of magnitude. Theseimprovements allow, for the first time, the use of simulation of background events inoscillation measurements performed by IceCube.Using the DeepCore detector, a densely instrumented infill of IceCube located in theclearest ice of the Antarctic glacier, a new selection of events has been created in the searchfor tau neutrino appearance from atmospheric oscillations. Tau neutrino appearanceand muon neutrino disappearance were measured simultaneously with the new samplefrom 5.6 to 56 GeV from data collected over a period of 968 days. The best fit values,NCC = 0.566+0.356−0.303 for the charged current exclusive channel and NNC+CC = 0.733+0.305−0.243for the neutral current inclusive channel, improve upon previous measurements set byother experiments

AB - Neutrino have been known to oscillate between the three flavors since the firstdiscoveries two decades ago. Over that time, our knowledge of the parameters whichgovern these oscillations has improved significantly. The largest remaining uncertaintiesin the measurement of neutrino oscillations are those that govern the tau neutrino. In thisthesis, a direct measurement of tau neutrino oscillations is performed with the IceCubeNeutrino Observatory located in the ice deep beneath the South Pole.The measurement of atmospheric tau neutrino appearance requires a precise understandingof backgrounds. In order to perform the measurement, improvements to themodeling of the detector noise have been performed, reducing the uncertainties in thenoise model used in IceCube significantly. Additional improvements to the simulationefficiency investigated during this thesis reduce the computational requirements of atmosphericmuon background events by more than three orders of magnitude. Theseimprovements allow, for the first time, the use of simulation of background events inoscillation measurements performed by IceCube.Using the DeepCore detector, a densely instrumented infill of IceCube located in theclearest ice of the Antarctic glacier, a new selection of events has been created in the searchfor tau neutrino appearance from atmospheric oscillations. Tau neutrino appearanceand muon neutrino disappearance were measured simultaneously with the new samplefrom 5.6 to 56 GeV from data collected over a period of 968 days. The best fit values,NCC = 0.566+0.356−0.303 for the charged current exclusive channel and NNC+CC = 0.733+0.305−0.243for the neutral current inclusive channel, improve upon previous measurements set byother experiments

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122547562405763

M3 - Ph.D. thesis

BT - A Search for Tau Neutrino Appearance with IceCube-DeepCore

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -