We discuss the spectrum of the different components in the astrophysical neutrino flux reaching the Earth, and the possible contribution of each component to the high-energy IceCube data. We show that the diffuse flux from cosmic ray (CR) interactions with gas in our galaxy implies just two events among the 54-event sample. We argue that the neutrino flux from CR interactions in the intergalactic (intracluster) space depends critically on the transport parameter Î´ describing the energy dependence in the diffusion coefficient of galactic CRs. Our analysis motivates a neutrino spectrum with a drop at PeV energies that fits the data well, including the non-observation of the Glashow resonance at 6.3 PeV. We also show that a CR flux described by an unbroken power law may produce a neutrino flux with interesting spectral features (bumps and breaks) related to changes in the CR composition.
Carceller, J.M., Illana, J.I., Masip, M., Meloni, D. (2018). Origin of the High-energy Neutrino Flux at IceCube. THE ASTROPHYSICAL JOURNAL, 852(1), 59 [10.3847/1538-4357/aa9d94].