Abstract:
Apart from the cosmic microwave radiation background, the standard cosmology predicts a thermal neutrino background with a temperature around 20K. Methods suggested to detect such a background, include anomalous forces exerted in sensitive devices, rotation of a polarized laser beam, etc. These are briefly reviewed. If the cosmic ray neutrino spectrum extends to the highest conceivable energies, one would expect interactions of these neutrinos with the background thermal neutrinos. Charged Lepton pair production arising in such interactions can cause dips in the UHE neutrino spectrum. Moreover one would expect resonant interactions at the W and Z masses and also at other energies if there are extra bosons beyond the standard electroweak model. The probabilities for the interactions of UHE cosmic ray neutrinos with the Dark Matter neutrino galactic holes are calculated taking all the above process into account. The dips in the UHE neutrino spectrum due to such interactions (which are potentially observable in DUMSAND or AMANDA etc.) is estimated. Other consequences are explored.
