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Marjon Moulai (MIT) “Unstable Sterile Neutrinos in IceCube and Beyond
January 14, 2020 @ 4:00 pm - 5:00 pm
Long-standing anomalies in short-baseline neutrino oscillation experiments suggest the existence of a new particle: the sterile neutrino. Unlike other neutrinos, sterile neutrinos do not interact via the weak nuclear force. Global fits to experimental data find a significant preference for a 3+1 sterile neutrino model, which introduces a fourth, heavier mass eigenstate, over the Standard Model with three massive neutrinos. However, disagreement between the preferred parameter regions in the appearance and disappearance datasets suggest that something beyond the 3+1 model is needed. In this talk, I will address this problem in two ways: the first is a new, unique search for sterile neutrinos, and the second is an unstable sterile neutrino model. IceCube, a gigaton ice-Cherenkov detector, is uniquely sensitive to a signature of sterile neutrinos that occurs for neutrinos traversing the earth at TeV energies. I will present the new 3+1 sterile neutrino search result from IceCube using eight years of data. Then I will discuss a sterile neutrino model involving neutrino decay. I will present: the phenomenology of this model in the case of IceCube; the result of incorporating IceCube data into recent global fits; and finally, the status of an eight-year search for unstable sterile neutrinos in IceCube.