Measurement of Atmospheric Neutrino Oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (> 20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010-2011. This measurement is made possible by the low energy threshold of the DeepCore detector (?20 GeV) 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. Disappearance of low-energy upward-going muon neutrinos was observed, and the non-oscillation hypothesis is rejected with more than 5? significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters ?m223=(2.3+0.6?0.5)?10?3 eV2 and sin2(2?23)>0.93, and maximum mixing is favored.