Discuss the properties of neutrino and its role in beta decay.

Explanation

Initially , it was thought that during beta decay, a neutron in the parent nucleus is convereted to the daughter nuclei by emitting only electron as given by
`""_(Z)^(A)"X" to ""_(Z+1)^(A)"Y" + e^(-)`
But the kinetic energy of electron coming out of the nucleus did not match with the experimental results. In alpha decay, the alpha particle takes only certain allowed discrete energies whereas in beta decay, it was found that the beta particle(i.e , electron)have a continuous range of energies.
But the conservation of enrgy and momentum gives specific single values for electron energy and the recoiling nucleus Y. It seems that the conservation of energy, momentum are violated and could not be explained why energy of beta particle have continuous range of values. So beta decay remained as a puzzle for several years.
After a detailed theoretical and experimental study, in 1931 W. Pauli proposed a third particle which must be present in beta decay to carry away missing energy and momentum. Fermi later named this particle the neutrino (little neutral one) since it has no charge, have very little mass.
For many years, the neutrino(symbol v, Greek nu) was hypothetical and could not be verified experimentally. Finally, the neutrino was detected experimentally in 1956 by Fredrick Reines and Clyde Cowan. Later Reines received Nobel prize in physics in the year 1995 for his discovery.
The neutrino has the following properties
It has zero charge
It has an antiparticle called anti-neutrino.
Recent experiments showed that the neutrino has very tiny mass.
It interacts very weakly with the matter.Therefore, it is very difficult to detect. In fact, in every second, trillions of neutrinos coming from the sum are passing through our body without any interaction.