Introduction to the Physics of Electroweak Interactions is a six-chapter book that first elucidates the deep-inelastic and elastic lepton scattering on nucleons (both cases of polarized and nonpolarized initial particles). Subsequent chapter presents a brief history of the construction of the phenomenological V-A weak interaction Hamiltonian. Other chapters detail the Glashow-Weinberg-Salam unified theory of weak and electromagnetic interactions; the processes in which neutrinos take part; and processes due to neutral currents, deep-inelastic neutrino-nucleon scattering, elastic neutrino-nucleon scattering, and elastic neutrino-electron scattering. This book will be useful to those who wish to master the techniques for calculating the experimentally measured quantities.

A graduate-level description of how the theory of electroweak interactions, or so-called "Standard Model" unifies the weak and electromagnetic forces of nature in high energy physics.

After an introduction to relativistic quantum mechanics, which lays the foundation for the rest of the text, the author moves on to the phenomenology and physics of fundamental interactions via a detailed discussion of the empirical principles of unified theories of strong, electromagnetic, and weak interactions. There then follows a development of local gauge theories and the minimal standard model of the fundamental interactions together with their characteristic applications. The book concludes with further possibilities and the theory of interactions for elementary particles probing complex nuclei. Numerous exercises with solutions make this an ideal text for graduate courses on quantum mechanics and elementary particle physics.

The papers contained in this volume are invited lec tures presented at the 21st "Universit~tswochen fUr Kern physik" in Schladming in February 1982. To consider electro magnetic and weak interactions as manifestations of a single theory is a standpoint, which is generally accepted by now. The goal of the school was to outline the present state of this unified theory and to discuss possible future developments. Thanks to the generous support provided by the Austrian Ministry of Science and Research, the Styrian Government and other sponsors, it was again possible to invite experts in the field as lecturers. The lecture notes have been reexamined by the authors and are now published in their final form to enable a larger number of physicists to profit from them. Since the lectures are already quite voluminous, we have decided to restrict the publication to the lectures themselves and omit all seminars, interesting as they were, as well as all details connected with the meeting. It is a pleasure to thank all the lecturers for their efforts, making it possible to speed up publication. Thanks are also due to L. Pittner for organisation and proof-reading as well as to Mrs. Krenn and Mrs. Neuhold for the careful typing of the papers. H. Mitter Acta Physica Austriaca, Suppl. XXIV, 3-62 (1982) © by Springer-Verlag 1982 INTRODUCTION TO GAUGE THEORIES OF ELECTRO + WEAK INTERACTIONS by G. ECKER Institut fUr Theoretische Physik Universitat Wien, Austria TABLE OF CONTENTS I

This book offers a self-contained introduction to the theory of electroweak interactions based on the semi-classical approach to relativistic quantum field theory, with thorough discussion of key aspects of the field. The basic tools for the calculation of cross sections and decay rates in the context of relativistic quantum field theory are reviewed in a short, but complete and rigorous, presentation. Special attention is focused on relativistic scattering theory and on calculation of amplitude in the semi-classical approximation. The central part of the book is devoted to an illustration of the unified field theory of electromagnetic and weak interactions as a quantum field theory with spontaneously broken gauge invariance; particular emphasis is placed on experimental confirmations of the theory. The closing chapters address the most recent developments in electroweak phenomenology and provide an introduction to the theory and phenomenology of neutrino oscillations. In this 2nd edition the discussion of relativistic scattering processes in the semi-classical approximation has been revised and as a result intermediate results are now explicitly proven. Furthermore, the recent discovery of the Higgs boson is now taken into account throughout the book. In particular, the Higgs decay channel into a pair of photons, which has played a crucial role in the discovery, is discussed. As in the first edition, the accent is still on the semi-classical approximation. However, in view of the necessity of a discussion of H !, the authors give several indications about corrections to the semiclassical approximation. Violation of unitarity is discussed in more detail, including the dispersion relations as a tool for computing loop corrections; the above-mentioned Higgs decay channel is illustrated by means of a full one-loop calculation; and finally, loop effects on the production of unstable particles (such as the Z0 boson) are now discussed. Finally, the neutrino mass and oscillation analysis is updated taking into account the major achievements of the last years.