The existence of the cosmic neutrino background (CνB) is predicted by Big Bang Theory, and its properties are closely related to the ones of the cosmic microwave background, which is measured with amazing accuracy. Although belonging to the most abundant particles of the universe, the relic neutrinos evade direct detection so far.
Cosmological probes provide limits on neutrino parameters, but their sensitivity is due to the gravitational interaction of the neutrinos solely, except for Big Bang Nucleosynthesis. Furthermore, these observations require a highly model dependent interpretation and in addition do not prove the existence of the CνB of today.
In this work, we explore the feasibility to detect the cosmic neutrino background in a more direct way, i.e. by means of scattering based experiments aiming for the present day relic neutrinos. We approach the problem using different methods and take advantage of the recent improvements in the experimental bounds on the neutrino masses and mixings as well as the cosmological parameters. For the detection of the low energetic relic neutrino flux at Earth by elastic scattering on nuclei in a torsion balance experiment, experimental progress beyond the estimates for the next decade is required. CνB detection via inverse beta decay at hadron colliders presents no promising option for the conceivable future. The most promising approach to detect the CνB within the next decade, is provided by the analysis of absorption dips in the extreme energy cosmic neutrino (EECν) flux. For these to be revealed with statistics sufficient for CνB detection, almost certainly a quasi-degenerate neutrino mass spectrum and a flux as large as the cascade limit are required. Absorption dips are most sensitive to neutrino properties, therefore they can be claimed to present the most solid proof of the CνB.