# The Proposal for the Neutrino

1. Mar 10, 2009

### americanforest

A historical question:

The neutrino was proposed by Pauli in 1930/31 to solve the crisis caused by the continuous energy distribution of the beta rays (electrons). The neutron was not discovered until 1932. Was Pauli aware, or did he even suspect, at the time of his proposal, the violation of angular momentum presented by beta decay without his neutrino? Please, if you find any sources, let me know.

2. Mar 10, 2009

### Bob S

In 1930 Wolfgang Pauli proposed a solution to the missing energy in nuclear beta decays, namely that it was carried by a neutral particle This was in a letter to the Tubingen congress. Enrico Fermi in 1933 named the particle the "neutrino" (meaning "small neutron", which it is not) and formulated a theory for calculating the simultaneous emission of an electron with a neutrino. Pauli received the Nobel Prize in 1945 and Fermi in 1938. The problem in detection was that the neutrinos could penetrate several light years depth of ordinary matter before they would be stopped.

In 1951 Fred Reines at Los Alamos thought about doing some real challenging physics problem. In a conversation with Clyde Cowan they decided to work on detecting the neutrino. Their neutrino detector was placed near the new Savannah River nuclear reactor in 1955. The detection of the (anti) neutrino was as the initiator of the inverse-beta decay reaction of:

anti-neutrino + proton -> neutron + positron.

Their target was water with CdCl_2 dissolved in it.