FROM CURRENT TO CONSTITUENT QUARKS - A RENORMALIZATION-GROUP-IMPROVEDHAMILTONIAN-BASED DESCRIPTION OF HADRONS

A model which combines the perturbative behavior of QCD with low-energ y phenomenology in a unified framework is developed. This is achieved by applying a similarity transformation to the QCD Hamiltonian which r emoves interactions between the ultraviolet cutoff and an arbitrary lo wer scale. Iteration then yields a renormalization-group-improved effe ctive Hamiltonian at the hadronic energy scale. The procedure preserve s the standard ultraviolet behavior of QCD. Furthermore, the Hamiltoni an evolves smoothly to a phenomenological low-energy behavior below th e hadronic scale. This method has the benefit of allowing radiative co rrections to be directly incorporated into nonperturbative many-body t echniques. It is applied to Coulomb gauge QCD supplemented with a low- energy linear confinement interaction. A nontrivial vacuum is included in the analysis via a Bogoliubov-Valatin transformation. Finally, the formalism is applied to the vacuum gap equation, the quark condensate , and the dynamical quark mass.