摘要
In a recent paper, we have shown that the neutrinos may contribute 99% of the mass in the universe, and only about 1% of it is due to baryons. Furthermore, such a huge mass of neutrinos will lead to the closeness of the universe. Therefore, it is of prime importance to detect the possible existence of the neutrino background in the universe.From recent particle physics experiments, it is known that there exist 3 types of neutrinos with presumably different masses: v_e,, v_μ and v_τ. They may even not correspond to the mass eigenstates. There are in principle 2 kinds of methods for detect-
