Identification of the Neutrino

In 1932, physics was certainly still fairly easy. Truth be told there were two understood force fields: gravity and EM (the strong field was yet to appear) and several recognized atomic particles: the electron, the proton as well as the neutron. (I am still dubbing them particles just as traditional practices, nevertheless keep in mind that in QFT these are field quanta.) To add in yet another particle or field to this practical, satisfying understanding of nature seemed to be unimaginable. However, there really was this irritating enigma in regard to beta rot.

Pauli’s postulated particle. A clue to the mystery became that the discharged beta rays contain a variety of energies, meaning that some energy must absolutely be going somewhere else. This led Wolfgang Pauli to suggest that in case a second particle is expended from the nucleus at the same instant as the electron, it could easily transport the unaccounted-for energy. He referred to the theoretical particle the “neutron”, however the instant that name was usurped by Rutherford a couple of years down the road, Enrico Fermi relabelled Pauli’s particle the neutrino (Italian for “little neutral one”).

wolfgangpauli“I admit that my expedient may seem rather improbable from the first, because if neutrons [i.e., neutrinos] existed, they would have been discovered long since. Nothing ventured, nothing gained … We should therefore be seriously discussing every path to salvation.”— W. Pauli (quoted in F. Reines’ Nobel lecture, 1995).

 

Discovery of the Strong Force

yukawa_postcardYukawa, child of a geology professor, graduated from Kyoto University in 1929. Five years later, while a resurgent militarism was swallowing up Japan which would certainly wind up in the infiltration of China in 1937 and the attack on Pearl Harbor in 1941, Yukawa provided the solution to the nuclear force quandary that had actually stumped Western scientists for over 20 years. The Yukawa field, as it is often called, then joined the stature of the gravitational and EM fields as the third fundamental force field in nature.

Starting from the analogy with Maxwell’s equations, Yukawa created a field equation which contains a new term that transforms the force coming from a slowly-varying one, like EM along with gravity, into one which diminishes rapidly– in truth, exponentially. The new term contains a constant which he named lambda, and by selecting lamba properly, Yukawa had the ability to make the theoretical range of the strong force match the experimentally-determined value. Yukawa thus accomplished precisely what Maxwell had actually carried out EM forces. He started off with a force that was without a doubt understood less well in comparison to EM forces, devised a mathematical articulation with regard to it, and surmised the field equations which would certainly characterize the force. But the best was yet to come…