Quarks and Strings on a Lattice

Abstract

Three lectures describe the lattice version of the color gauge theory of quarks. The string interpretation of the theory is emphasized. The strong coupling expansion is defined by a set of Feynman rules. The dominant diagrams are identified. The result is that for strong quark-gluon coupling, the lattice spacing is about 1/5 x 10−13cm, the nucleon has a mass of 1720 MeV/c2 while the N* mass is 1750 MeV/c. The π and ρ masses are fitted to experiment. The relativistic limit is explained for free field theories on a lattice. For the colored quark theory only a few aspects of the relativistic continuum limit are discussed. It is shown how short wavelength string fluctuations are suppressed. It is shown that the classical limit of the lattice theory is the relativistic continuum color gauge theory.