AN INTRODUCTION TO THE STANDARD MODEL OF PARTICLE PHYSICS
W.N. Cottingham and D.A. Greenwood, Cambridge University Press, 1998, pp: xviii+235, ISBN 0-521-58832-4 (pbk; -58191-5 hc), QC794.6.S75C68, Price: $29.95 (pbk; $74.95 hc)

This is an introductory graduate level textbook on the standard model of particle physics, suitable for anyone with a typical undergraduate background in classical and quantum mechanics, special relativity, and electromagnetism. In such a slender volume (230 pages) not all topics in particle physics can possibly be covered, as implied by the title; instead the authors focus on providing an account of the gauge theories of the electroweak and strong interactions. There is little discussion of phenomenology, history or experimental techniques, and little about the pioneering experiments of particle physics and the colourful physicists responsible for the breakthroughs.

This book provides, instead, a detailed introduction to the theoretical framework of the standard model, and this it does very well. After an introductory chapter on leptons, quarks, colour, as well as three paragraphs on particle accelerators, the authors start on the material proper with a chapter on Lorentz transformations, 4-vectors and tensors. The Lagrangian formulation of mechanics is reviewed and extended to the Lagrangian density for a continuous system. The Lorentz-invariant Lagrangian density leading to the Klein-Gordon equation is presented. The Lagrangian density for electromagnetism is found and extended to massive vector fields. The Dirac equation and its free space solutions are studied. The EM field is quantized and the reader is shown how to calculate the first order term in the perturbation theory expansion for the interaction of a Dirac electron with the EM field, but the Feynman rules are neither derived nor even stated. I feel that this is a golden opportunity missed; just knowing the Feynman rules allows a student to calculate a great many important low-order processes in QED. As well, the intuitively appealing Feynman approach of thinking of positrons as "electrons going backwards in time" is not used in this book. The Weinberg-Salam theory of electroweak interactions and its experimental tests are discussed in detail. QCD is then presented as another gauge theory, and the results of perturbative QCD at high energies and lattice QCD at low energies are discussed. There is no discussion of baryon or meson spectroscopy, apart from a brief discussion of charmonium and bottomonium; the reader could finish this book without knowing what the pion or eta mesons are, or what the quark compositions of a proton or Lambda are. There are a few places where the authors assume background knowledge that would be lacking in a true beginner in particle physics. For example, in the first chapter, the authors give examples of some Feynman diagrams contributing to electron-quark scattering, without ever having explained what a Feynman diagram is. The style of writing is terse and to-the-point.

This book is suitable for a course on the modern theory of particle physics. It would also be a useful complement to a more phenomenological book such as Perkins, since one is strong where the other is weak. The low price for the paperback version will make it attractive to students.

Stanley Yen,
TRIUMF