In 1914 James Chadwick observed that the electron emitted in the beta-decay of radioactive nucleus does not emerge with one definite kinetic energy but rather with a continues spectrum of energies. The final state of the beta-decay of an unstable nucleus was assumed to consist of only tow particles: the daughter nucleus and the electron.
In 1930 the neutrino was only first postulated theoretically by Wolfgang Pauli. For many years it was considered a massless particles. The history of the neutrino began with the investigation of beta-decay.
Pauli proposed that there could exist another neutral particle emitted in beta-decay which carried away the missing energy and made the electron energy spectrum continuous.
In 1934, Enrico Fermi formalized the proposal for the neutrino, which he posited as having zero rest mass, no electrical charge and a spin of one half.
Before the 1950’s, all of the experiments were designed to observe the energy and momentum carried away by the neutrino in the beta decay.
In 1956, the neutrino was discovered by Frederick Reines and Clyde L. Cowan. The experiment took place at the Savannah River nuclear reactor in South Carolina.
Pauli announced the news of the detection by Reines and Cowan when he gave a seminar at the CERN symposium on high energy accelerator and pion physics in July 1956.
These discoveries create a number of new fundamental questions and opportunities to further advance human understanding of the universe and the laws that govern it.
Discovery of Neutrino
