ELEMENTS OF QUANTUM CHROMODYNAMICS [chapter]

2009 World Scientific Lecture Notes in Physics  
see, the situation is not quite that bad. However, X think perturbative QCD is much mora restricted than QED, for reasons that hopefully become clearer as we proceed. These lectures will concentrate for the most part on the Book II approach. Tht.^ is not meant to imply disparagement of the Book X method; Stan Brodsky will most ably cover that. 2 Nor is it meant to downgrade other approaches, in particular those based on path-integral formulations. 3 Indeed) use of path-integral techniques has
more » ... al techniques has thus far been the most success ful mode of attack on the difficult mathematical problems posed by QCD. The rules for-diagrams are most efficiently derived in that way (especially in correctly accounting for the subtleties associated ,.lth Faddeev-Popov ghosts). Also the demonstration of confinement in strong-coupling lattice QCD acid the studies of instantons are best done within the path-Integral formalism. Our rationale for avoiding it here is simply to look at the subject in a slightly different way [after all, some problems, such as the hydrogen atom, are more difficult using path-Integrals]. as well as to spare the less theoretically oriented reader the unavoidable preliminary technology needed to set up the path-integral formalism. In any case, the problem confronting everyone is difficult; all attacks should be brought to bear. We shall classify the subject-matter into three stages oE increasing complexity. In the first we consider "pure" QCD in the absence of any ferr Ions or other sources. The QED analogue is the (trivial) theory of free non-interacting photons. For QCD this Is presumably the (nontrivial) theory of interacting gluonium (color-singlet bound glue) states. The second stage allows the introduction only of superheavy quarks in addition ,lU . " W.3B) |j5 • |(x) -«£"MJ%
doi:10.1142/9789812793553_0002 fatcat:kxwpbgpcjbdx3guqzjwjuyqlnq