4 QCD: The Theory of Strong Interactions

Abstract

This chapter is devoted to a concise introduction to quantum chromodynamics (QCD), the theory of strong interactions (Gell-Mann, Acta Phys Austriaca (suppl. IX):733, 1972; Gross and Wilczek, Phys Rev Lett 30:1343, 1973; Weinberg, Phys Rev Lett 31:494, 1973) [for a number of dedicated books on QCD, see Dokshitzer and Khoze (In: Frontieres (ed) Basics of perturbative QCD, 1991), and also Altarelli (QCD: the theory of strong interactions. In: Landolt-Boernstein I 21A: Elementary particles 4. Springer, Berlin, 2008)]. The main emphasis will be on ideas without too many technicalities. As an introduction we present here a broad overview of the strong interactions [for reviews of the subject, see, for example, Altarelli (Phys Rep 81:1, 1982) and Altarelli (Ann Rev Nucl Part Sci 39:357, 1989)]. Then some methods of non-perturbative QCD will be briefly described, including both analytic approaches and simulations of the theory on a discrete spacetime lattice. Then we shall proceed to the main focus of the chapter, that is, the principles and applications of perturbative QCD, which will be discussed in detail.