Introduction

Abstract

One of the surprising facts in our present understanding of the development of the Universe is the complete absence of “primordial” antimatter from the Big Bang about 13.7 billion years ago. The detection of charged cosmicray particles by magnetic spectrometers borne by balloons, satellites, and the space shuttle has shown no evidence for such primordial (high-energy) antibaryons; nor has the search for gamma rays from antimatter-matter annihilation yielded any such observation. This phenomenon can only be explained if the three conditions of Sakharov are fulfilled: there must be an interaction violating CP invariance; there must be an interaction violating the conservation of baryon number; and there must be phases of the expansion without thermodynamic equilibrium. In this book, we shall concentrate on the observed CP violation, which could in principle lead to a small surplus of matter, the observed baryon asymmetry in the Universe.