The Proposal for the Neutrino

[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.

 

[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.

 

[sir-pinski]

This is a fascinating historical question that sheds light on the origins of one of the most elusive particles in the universe. While there is no definitive answer, there is evidence to suggest that Pauli may have been aware of the violation of angular momentum in beta decay at the time of his proposal.

One source that supports this is a letter written by Pauli to his colleague Lise Meitner in December 1930, in which he discusses his initial idea for the neutrino. In the letter, he mentions the possibility of a particle with zero mass and spin 1/2 that could carry away the missing energy and momentum in beta decay. This suggests that Pauli was aware of the need for a particle to conserve angular momentum in beta decay.

Furthermore, it is worth noting that Pauli's proposal was not immediately accepted by the scientific community. It was met with skepticism and criticism, and it was not until the discovery of the neutron in 1932 that the concept of the neutrino gained more widespread acceptance. This suggests that there may have been some awareness of the violation of angular momentum in beta decay at the time of Pauli's proposal.

However, it is also possible that Pauli's proposal was based solely on the need for a missing particle to conserve energy in beta decay, and he may not have been aware of the violation of angular momentum. Without concrete evidence or further correspondence from Pauli himself, it is difficult to definitively answer this question.

In conclusion, while there is no conclusive evidence, it is likely that Pauli was at least partially aware of the violation of angular momentum in beta decay at the time of his proposal for the neutrino. Further research and analysis may provide more insight into this historical question.