School of Chemistry and Physics, University of Adelaide, Adelaide South Australia 5005, Australia.
Phys Rev Lett. 2013 Jul 12;111(2):021103. doi: 10.1103/PhysRevLett.111.021103. Epub 2013 Jul 8.
We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.
我们报告了两个中微子引发事件的观测结果，它们在 IceCube 探测器中的估计沉积能量分别为 1.04±0.16 和 1.14±0.17 PeV，这是迄今为止观测到的最高中微子能量。这些事件与在 IceCube 探测器内由中性电流 ν(e,μ,τ)（ν(e,μ,τ)）或带电电流 ν(e)（ν(e)）引发的完全包含粒子簇射一致。这些事件是在使用对应于 615.9 天有效运行时间的数据搜索超高能中微子时发现的。大气背景的预期数量为 0.082±0.004(stat)(-0.057)(+0.041)(syst)。在仅考虑大气背景事件预期数量不确定性的情况下，在大气背景下观察到两个或更多候选事件的概率为 2.9×10(-3)（2.8σ）。这两个事件可能是天体物理中微子通量的第一个迹象；然而，由于其适度的显著性，目前还不能得出明确的结论。
