The First Gauge Theory of Weak Interactions and the Prediction of Weak Neutral Currents

摘要

The three theoretical and historical components of the Standard Model are theexact chiral gauge theory of weak interactions, electroweak unification, andthe Higgs mechanism for spontaneous symmetry breaking. I put into historicalperspective my 1958 invention of the first gauge theory of weak interactions,predicting weak neutral currents, and show how the fundamental differencesbetween global and gauge symmetries and between partial flavour and exact gaugesymmetries, emerged in the strong and weak interactions. Althoughrenormalizability is necessary for theoretical consistency, electroweakunification was not necessary, in principle. An interesting difference appearsbetween the $\sin^2{\theta_W}=0$ limit of the electroweak theory and theoriginal $SU(2)_W$ gauge theory of weak interactions. While the electroweakmixing angle might have had any value (including zero), historically the value$\sin^2{\theta_W} \sim 0.3$ actually observed in weak neutral currents gavecircumstantial support for the Standard Model and stimulated the search for$W-$ and $Z-$mesons.