Models with more than four quarks

Several models with more than four quarks are reviewed and compared with the four-quark model. They generally have right- and left-handed currents and are of the S${\mathrm{U}}_2$ × ${\mathrm{U}}_1$ type. The lepton sectors are also discussed including the possibilities of heavy charged and neutral leptons. The weak phenomenology, triangle anomalies, degenerate quark masses, and radial excitations are examined.