Enrico Fermi’s paper discussing neutrinos was rejected by journal Nature because “it contained speculations too remote from reality to be of interest to the reader.”Previous Fact Next Fact
Wolfgang Pauli can be seen as the somewhat reluctant father of the neutrino, being the first one to predict its existence but not being very happy to do so! Researchers had noticed that nuclear beta decay seemed to break the laws of conservation of energy and linear and angular momentum. Since the name neutron was now taken, Fermi gave it the name neutrino by which it goes today, meaning "The little neutral one". Despite Fermi's work in the 1930s, the neutrino at first did not draw many physicists' attention; in fact, it was considered to be a somewhat "Arrogant" particle, which simply ignored matter and whose one and only task was to carry off energy in beta decay. He explained the beta decay of a nucleus in terms of the creation and immediate emission of an electron simultaneously with an invisible neutrino. Pauli himself was so thoroughly convinced that the neutrino could not be detected that he actually bet a case of champagne that nobody would ever detect the neutrino. The neutrino is a lepton and comes in three different "Flavours": the electron neutrino in the first generation, the muon neutrino in the second generation and the tau neutrino in the third generation. In the late 1960s, Ray Davis of the Brookhaven National Laboratory, USA, began to think about experiments using neutrinos as potential probes of the Sun's interior.
The very first solar neutrino experiment was then carried out by him in the late 1960s using a technique from radiochemistry. Suitable nuclei would be those which very occasionally underwent a nuclear reaction triggered by an incoming solar neutrino from Boron-8 decay. Various laboratory experiments had provided sound knowledge on nuclear properties of Argon-37 and Chlorine-37 from which theoretical calculations concerning the electron neutrino capture cross section of Chlorine-37 could be made and hence it was possible to infer the solar electron neutrino flux. Right from the beginning, it was acknowledged that the observed flux of Boron-8 decay reaction neutrinos was substantially less than that predicted by the solar model, assuming that nothing happened to the electron neutrinos after they were created inside the sun. The observed discrepancy became known as the "Solar neutrino problem", which over the following decades became a great source of confusion and speculation among particle and astrophysicists. Due to the scepticism prevailing among many particle physicists, much time from 1968 onwards was spent investigating the robustness of the solar model predictions of neutrino fluxes, instead of looking for insufficiencies in the standard model. It took several more sophisticated experiments including GALLEX and SAGE to finally prove in 1990 that the problem did not lie with the solar model by showing that the low-energy neutrinos were missing too. At this time, the "Solar neutrino problem" had long turned into a major field of physics research, since it was becoming more than obvious that new physics had been found that needed explanation.