There are currently two major QCD-inspired quark models for hadrons. Nonrelativistic potential models and ultrarelativistic bag models have both had their successes. In this paper we present the case for an alternative quark picture, emphasizing the nonperturbative dynamical breaking of chiral symmetry in QCD. The relativistic constituent quark model which emerges recovers the main results of the other approaches, and also holds better prospects for the calculation of relativistic phenomena, and for the eventual understanding of the interrelations between chiral-symmetry breaking, hadron structure and confinement.
Constituent quark models and pentaquark baryons
