A Possible Two-component Flux for the High Energy Neutrino Events at IceCube

Understand

Understanding the spectral and flavor composition of the astrophysical neutrino flux responsible for the recently observed ultra-high energy events at IceCube is of great importance for both astrophysics and particle physics.

• We perform a statistical likelihood analysis to the 3-year IceCube data and derive the allowed range of the spectral index and flux normalization for various well-motivated physical flavor compositions at source.
• While most of the existing analyses so far assume the flavor composition of the neutrinos at an astrophysical source to be (1:2:0), it seems rather unnatural to assume only one type of source, once we recognize the possibility of at least two physical sources.
• Bearing this in mind, we entertain the possibility of a two-component source for the analysis of IceCube data.