Collider experiments have become essential to studying elementary particles. In particular, lepton collisions such as e⁺e⁻ are ideal from both experimental and theoretical points of view, and are a unique means of probing the new energy region, sub-TeV to TeV. It is a common understanding that a next-generation e⁺e⁻ collider will have to be a linear machine that evades beam-energy losses due to synchrotron radiation. In this book, physics feasibilities at linear colliders are discussed in detail, taking into account the recent progress in high-energy physics.

The high energy electron-positron linear collider is expected to provide crucial clues to many of the fundamental questions of our time: What is the nature of electroweak symmetry breaking? Does a Standard Model Higgs boson exist, or does nature take the route of supersymmetry, technicolor or extra dimensions, or none of the foregoing? This invaluable book is a collection of articles written by experts on many of the most important topics which the linear collider will focus on. It is aimed primarily at graduate students but will undoubtedly be useful also to any active researcher on the physics of the next generation linear collider.

Two-photon physics, i.e. photon-photon collisions in electron-positron colliders, a relatively new field in elementary particle physics, has become very popular in the last 20 years. Many experiments have been performed in this field, and the theoretical implications (in particular in quantum chromodynamics) have been studied in much detail. Nine international workshops devoted to two-photon physics have taken place between 1973 and 1992.This meeting was particularly timely, since a new generation of electron-positron colliders is presently being built or planned. These colliders will involve a large spectrum of beam energies, but their common characteristics should be a high particle flux (luminosity). This should allow for measuring many new phenomena as well as for studying known processes with much higher precision than before. Particularly promising is the prospect of building a dedicated high-energy photon collider; this should become possible using a laser technique allowing for the “conversion” of a linear electron beam into a photon beam.Over 60 physicists (both experimentalists and theorists), mainly from European countries (France, Britain, Italy, Germany, Russia, as well as Sweden and Switzerland), discussed these new possibilities at the above meeting. Over 30 talks were presented and many extended debates took place.

Nuclear nonproliferation is a critical global issue. A key technological challenge to ensuring nuclear nonproliferation and security is the detection of long-lived radioisotopes and fissionable nuclides in a non-destructive manner. This technological challenge requires new methods for detecting relevant nuclides and the development of new quantum-beam sources. For example, one new method that has been proposed and studied is nuclear resonance fluorescence with energy-tunable, monochromatic gamma-rays generated by Compton scattering of laser photons with electrons.The development of new methods requires the help of researchers from a wide range of fields, such as nuclear physics, accelerator physics, laser physics, etc. Furthermore, any new method must be compatible with the requirements of administrators and nuclear-material inspectors.