The bag model of hadrons

Abstract

The bag model of hadrons, particularly in the form invented at MIT, is reviewed. After a discussion of the reasons for believing that hadrons are bound states of quarks which behave as almost free Dirac particles, the authors present a formal treatment of the bag model in one space dimension. Here the classical problem has an exact solution but there are difficulties in developing a satisfactory quantum theory. The last two sections deal with the phenomenological bag model in three space dimensions and compare its predictions with experiment. In general, the model provides a satisfactory framework for treating hadrons as systems of confined quarks, with a residual QCD interaction that need only be considered in lowest order. Where the details of the confinement mechanism is important, however, the model shows some signs of being unsatisfactory.