Nucleon nucleon potential using Dirac constraint dynamics

The relativistic potential concept is fostered for the description of nucleon-nucleon (NN) interactions and scattering for energies 0 < TLab ≤ 3 GeV. It proves useful to confirm and predict nuclear properties and reactions with the implicit knowledge having the best possible agreement with experimental NN data. Medium energy NN scattering, as is accepted for low energy nuclear physics in general, is determined from proton, nucleon and meson degrees of freedom in the long range soft interaction sector, the quark gluon degrees of freedom govern the short distance hard processes. The identification and parameterization, of the combined long and short range NN domains, is the topic of this thesis. The formalism for two coupled Dirac equations, within constraint instant form dynamics, is used to study the NN interaction. The comprehensive review, of the important theoretical tools and associated mathematics, rests essentially on the work of Crater and Van Alstine. The reduction of the coupled Dirac equations into Schroedinger type equations is given. Explicitly energy dependent coupled channel potentials, for use in partial wave Schroedinger like equations, with nonlinear and complicated derivative terms, result. We developed the necessary numerics and study np and pp scattering phase shifts for energies 0 to 3 GeV and the deuteron bound state. The interactions are inspired by meson exchange of π, η, ρ, ω and σ mesons for which we adjust coupling constants. This yields, in the first instant, high quality fits to the Arndt phase shifts 0 to 300 MeV. Second, the potentials show a universal, independent from angular momentum, core potential which is generated with the relativistic meson exchange dynamics. Extrapolations towards higher energies, up to TLab equal 3 GeV, allow to separate a QCD dominated short range zone as well as inelastic nucleon excitation mechanism contributing to meson production. A local or nonlocal optical model, in addition to the meson exchange Dirac potential, produces agreement between theoretical and phase shifts data. The optical model potentials reflect a short lived complex multi hadronic intermediate structure formation of which the optical model parameters give a consistent picture. For future work, the here presented phenomenological access encourages a more microscopic and detailed use of QCD, including explicit Δ(3, 3) pair formation and some obviously predominant other pair mechanism. (orig.)