Editing Electroweak interaction (section)

== History ==
After the [[Wu experiment]] in 1956 discovered [[parity violation]] in the [[weak interaction]], a search began for a way to relate the [[weak interaction|weak]] and [[electromagnetic interaction]]s. Extending his [[doctoral advisor]] [[Julian Schwinger]]'s work, [[Sheldon Glashow]] first experimented with introducing two different symmetries, one [[Chirality (physics)|chiral]] and one achiral, and combined them such that their overall symmetry was unbroken. This did not yield a [[renormalization|renormalizable]] [[gauge theory|theory]], and its gauge symmetry had to be broken by hand as no [[Spontaneous symmetry breaking|spontaneous mechanism]] was known, but it predicted a new particle, the [[Z boson]]. This received little notice, as it matched no experimental finding.

In 1964, [[Abdus Salam|Salam]] and [[John Clive Ward]]<ref>{{Cite journal|last1=Salam|first1=A.|last2=Ward|first2=J.C.|date=November 1964|title=Electromagnetic and weak interactions|url=https://linkinghub.elsevier.com/retrieve/pii/0031916364907115|journal=Physics Letters|language=en|volume=13|issue=2|pages=168–171|doi=10.1016/0031-9163(64)90711-5|bibcode=1964PhL....13..168S |url-access=subscription}}</ref> had the same idea, but predicted a massless [[photon]] and three massive [[gauge boson]]s with a manually broken symmetry. Later around 1967, while investigating [[spontaneous symmetry breaking]], Weinberg found a set of symmetries predicting a massless, neutral [[gauge boson]]. Initially rejecting such a particle as useless, he later realized his symmetries produced the electroweak force, and he proceeded to predict rough masses for the [[W and Z bosons]]. Significantly, he suggested this new theory was renormalizable.<ref name=Weinberg1967/> In 1971, [[Gerard 't Hooft]] proved that spontaneously broken gauge symmetries are renormalizable even with massive gauge bosons.