| Over the last two decades a revolution has taken place concerning the way physicists view the fundamental processes taking place in our universe. This revolution has its basis in the belief that all fundamental interactions are associated with a particularly beautiful and powerful kind of quantum field theory-a theory of local gauge fields. This tenet of faith is termed the gauge principle. These theories certainly satisfy the criterion of beauty, and they have passed sufficient experimental tests to ensure that they are at least approximately correct for the weak, electromagnetic, and strong interactions. There is even some indication that superstring theory may bring gravitation into the unified gauge fold, but this is presently far from certain.
The intent of this book is to allow a person who has little background in elementary particle physics and quantum field theory to acquire sufficient expertise to speak the language and to confront the literature in this and related disciplines. In particular, I have in mind three areas of research that should present challenging opportunities in the relatively near future for particle, nuclear, and astrophysicists. The first is an elaboration of the role that gauge field theories, or effective theories derived from gauge theories, play in nuclear physics: where are the quarks and gluons in nuclei, and what is their relation to the traditional nucleon and nleson degrees of freedom? There is considerable phenomenological understanding, but microscopically we have only scratched the surface of this problem. The second concerns the possibility of creating fundamental new states of matter such as an extended quark-gluon plasma in ultrarelativistic heavy ion collisions; this also is a field in its infancy. The third is the relation of gauge theories to the creation and evolution of the universe: what role do these theories play in cosmology, and how does cosmology test and illuminate our understanding of elementary particle physics? |
