Q.C.D.; glue-balls and gluon mixing into hadrons

Having used the current understanding of Quantum Chromodynamics (QCD) to motivate the Bag model of hadrons and set up a systematic perturbation theory of QCD in a finite spherical cavity to tree approximation, these techniques are then used to reproduce, simply, some existing results of the Bag model which before had been derived using semi-classical methods. The techniques are also used to discuss the spectrum of bag states, consisting solely of gluons including hyperfine mass corrections, and to calculate the mixing of glue-balls and gluons with quark matter, with particular reference to the eta-eta0 problem. (U.K.)