Electroweak Unification

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Since the weak field must have spin 1, you will not be surprised to learn that it wound up in the same family as the EM field, the only other field with spin 1. Using the lepton family as a model, Julian Schwinger suggested that the two charged weak fields be joined with the neutral EM field to make a family of three fields with spin 1.

In theorizing merely two charged weak fields, Schwinger made the very same misstep that Yukawa had made concerning the strong field. It was Schwinger’s student, Sheldon Glashow, that added a neutral weak field. Ironically, Schwinger’s Z notation endured for the neutral field that he did not introduce, while the ones he did introduce were actually later renamed W.

As Schwinger’s doctoral scholar, Sheldon Glashow was actually given the task of actualizing Schwinger’s idea that the weak field was actually one component of a family of three fields with spin 1 (known as vector bosons).

Soon after completing his thesis, Glashow carried on his “assignment” at the Bohr Institute in Copenhagen. It was actually there that he ultimately recognized that in the event that weak interactions breach parity conservation while EM interactions do not, they can not be as closely linked as Schwinger thought. This led him to add a neutral weak field that he designated Zo, complying with Schwinger’s Z-notation, while at the same time transferring the photon to a more “cousinly” relationship.

You might think that this would have finished the matter, however there still continued to be a problem. The mass of these fields must be enormous that one may explain the feebleness related to the weak interactions (as illustrated by the prolonged half-lives with respect to beta decay), and there was no explanation for this kind of a sizeable mass.

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It was Steven Weinberg and also Abdus Salam (1926-1996) who independently formulated a method to clarify the large mass in 1967 and 1968. They carried this out by applying what is known as the Higgs mechanism (initially suggested by Schwinger in the same paper where he introduced the V and A equation). At the same time Weinberg replaced Schwinger’s Z notation for the charged weak fields to W (for weak– or even possibly Weinberg?), but maintained Z for the neutral field, leading to the present hybrid notation. For their success, Glashow, Weinberg and Salam shared the 1979 Nobel Prize, while Schwinger’s contribution was, as usual, essentially forgotten.

Just like with Pauli’s neutrino, it became clear that identifying the weak field quantum would pose a considerable challenge.

It was not until 1983 that substantiation for the weak field quantum was secured at the jumbo CERN accelerator in Geneva, Switzerland. All three quanta were detected: Schwinger’s charged fields and the neutral particle that Glashow introduced. The masses of the new field ended up being over 500 times greater than that of the strong field, making it the heaviest known quantum field– and its range thus the shortest. For this triumph, Carlos Rubbia and Simon van der Meer were presented the 1984 Nobel Prize in physics.
All three quanta were detected: Schwinger’s charged fields and the neutral particle that Glashow introduced. The masses of the new field turned out to be over 500 times greater than that of the strong field, making it the heaviest known quantum field– and its range therefore the shortest.

http://www.quantum-field-theory.net/electroweak-unification

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