We present a bottom-up and a top-down model that can produce high-energy neutrinos.
Gamma rays bursts (GRBs) are flashes of gamma rays which are associated with extremely high energetic explosions in distant galaxies. The relativistic fireball is the most popular model to explain the GRBs. Within the fireball model ultra-high energetic cosmic rays can be produced. It is also likely that neutrinos are produced at high energies, which should be detectable with the IceCube detector.
In a top-down approach ultra-high energetic cosmic rays are produced through the decay of superheavy dark matter (SHDM), particles with masses above 1013 GeV. SHDM can be formed in the early universe directly after the era of inflation following the instant preheating process by Felder, Kofman, and Linde. Annihilation of these SHDM particles inside the galactic DM halo could produce ultra-high energetic cosmic rays with energies above the GZK-cutoff.