Quarks and Leptons An Introductory Course in Modern Particle Physics
Francis Halzen and Alan D. Martin
Dramatic progress has been made in particle physics during the past two decades. A series of important experimental discoveries has firmly established the existence of a subnuclear world of quarks and leptons. The protons and neutrons (” nucleons”), which form nuclei, are no longer regarded as elementary particles but are found to be made of quarks. That is, in the sequence molecules ~ atoms ~ nuclei ~ nucleons, there is now known to be another “layer in the structure of matter.” However, the present euphoria in particle physics transcends this remarkable discovery. The excitement is due to the realization that the dynamics of quarks and leptons can be described by an extension of the sort of quantum field theory that proved successful in describing the electromagnetic interactions of charged particles.