This elementary particle was already proposed in 1930 by Wolfgang Pauli and in 1934 by Enrico Fermi , and gets detected experimentally by Clyde Cowan and Fred Reines in 1956. In addition to the electron-, antielectron-neutrino the discovery of the muon-, antimuon-neutrino in 1962 and the tau-, antitau-neutrino in 2000 followed.
Neutrinos have no charge, a very small mass and interact rarely with matter, which make them difficult to detect. During beta decay, a neutron converts into a proton, an electron and an antineutrino, which is emitted. Some of today's Research projects try to find out the concrete mass of neutrinos or if neutrinos can change from one neutrino type to another.