Chiral Symmetry and Strong Interactions

Strong interactions are described by a fundamental theory know as Quantum Chromodynamics QCD It is a gauge theory like the theory of electromagnetism but because of the nonlinear interactions of the gauge bosons many of its properties are due to nonperturbative physics In particular chiral symmetry breaking and confinement cannot be explained by means of an expansion in powers of the coupling constant Although we have schematic models to explain these phenomena the fundamental understanding of these nonperturbative properties is