Hidden gauge symmetry

The past 15 years has seen the gradual emergence of the idea that the fundamental physical interactions are determined by gauge symmetry or, more precisely, by hidden (spontaneously broken) gauge symmetry. The importance of gauge symmetry is that it reduces considerably the possible forms of interaction, gives the interactions a geometrical meaning, and introduces a certain degree of unification to the different known interactions (gravitational, weak, etc.). A description of the principles of hidden gauge symmetry and of its application ot the fundamental interactions is presented. The emphasis is on the structure, gauge symmetry and hidden symmetry are first treated as independent phenomena before being combined into a single (hidden gauge symmetry) theory. The main application of the theory is to the weak and electromagnetic interactions of the elementary particles, and although models are used for comparison with experiment and for illustration, emphasis is placed on those features of the application which are model-independent.