http://arxiv.org/abs/1310.5123
Cosmic rays diffuse through the interstellar medium and interact with matter and radiations as long as they are trapped in the Galactic magnetic field. The IceCube experiment has detected some TeV-PeV neutrino events whose origin is yet unknown.Assuming these events were produced in the interactions of cosmic rays with matter, we calculate the average matter density needed to explain them for different halo sizes and shapes, and we study the effect of the chemical composition of the cosmic rays. We find that the current neutrino observation can be described by a best-fit hydrogen target density of 1.6^+0.3_-0.5 cm^-3 for an effective halo size R_eff=10 kpc and a cosmic ray proton composition, whereas heavier nuclei imply higher target densities. It is also shown that a mixed composition model can, in principle produce a peak of the neutrino spectrum at PeV energies.
Date added: Mon, 21 Oct 13