Paper of the Week
Physics Review Letters,111,081801 (2013)
Besson*, D. Z. and the IceCube Collaboration
* KU Physics and Astronomy Authors
We present the first statistically significant detection of neutrino oscillations in the high-energy regime (> 20GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5 sigma significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Delta m_32^2|=(2.3_-0.5^+0.6) x 10^-3eV^2 and sin^2(2theta_23)>0.93, and maximum mixing is favored.