Speaker
Description
Longstanding anomalies observed in short-baseline neutrino oscillation experiments have motivated an eV-scale sterile neutrino. Because of matter effects within the Earth, the existence of this particle would cause a deficit in the atmospheric and astrophysical muon neutrino flux at TeV energies for neutrinos crossing the Earth. We present the results of a search for an unstable sterile neutrino in IceCube. In this model, the heaviest neutrino mass state may decay. The unstable sterile neutrino model is preferred to the three-neutrino model and 3+1 models with p-values of 2.5% and 0.81%, respectively. The best-fit parameters for the unstable sterile neutrino model are $\Delta m_{41}^2=6.7^{+3.9}_{-2.5}\,\rm{eV}^2$, $\sin^2 2\theta_{24}=0.33^{+0.20}_{-0.17}$, and $g^2=2.5\pi\pm1.5\pi$, where $g$ is the decay-mediating coupling. We find no evidence for the unstable sterile neutrino model.
| Collaboration | IceCube Collaboration |
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