TABLE OF CONTENTS In this chapter we review some basic phenomenology of the weak interactions. This material is the result of over a half-century of beautiful experimental and theoretical work, and we cannot really do justice to this material in a superficial overview. Nonetheless, a familiarity with the basic weak interaction phenomenology is essential to the further development in this part of the book. The reader is referred to [Wa75, Co83] for a much more extensive discussion of these topics and a thorough list of references to the original literature.
Most leptons (l, ? l ) are light, or massless, and they can be created and destroyed in weak interactions. This indicates that they must be described with relativistic quantum fields. In the interaction representation, fermion fields take the following form
| (42.1) |  |
In this expression a destroys a lepton, b creates an antilepton, and ? denotes the helicity with respect to the accompanying momentum variable. [1]
[1]Hole theory implies that ?( ? k ?) is a negative-energy wave function with helicity ? with respect to ? k.
In...
