Hochenergiestreuung im Nichtperturbativen Vakuum der Quantenchromodynamik [High-energy scattering in the nonperturbative vacuum of Quantum Chromodynamics]

Abstract

We consider scattering in nonperturbative Quantum Chromodynamics (QCD) for large invariant centre of mass energy $\surd s$. Our analysis is based upon the Stochastic Vacuum Model~(SVM) of Dosch and Simonov and on the nonperturbative $s\to \infty$-asymptotic formula of Nachtmann for the scattering of two Wegner Wilson loops. We argue, that its validity can be expanded to large but finite values of~$s$ by {\sl not} substituting the initial near light-like loops for their exact light-like limits. Thus, the $T$-amplitude depends on $s$ beyond the kinematical factor. This $s$-dependence is explicitly calculated. We conclude performing the analytical continuation to Euclidean spacetime and in that way make accessible high-energy scattering to Euclidean theories such as QCD lattice gauge theory. Based upon the $s\to \infty$-asymptotic formula, we further calculate exclusive photo- and leptoproduction of a vectormeson at the proton: ${\text{ga}}^{(\ast )}p\to Vp$}, -- for $V\equiv \rho (770),\omega (782),\varphi (1020),J/\psi (3097)$ and $\text{rh}(1450),\text{rh}(1700)$. Essential entities are the photon light-cone wave function of light-cone perturbation theory (LCPT) universalised to vanishing virtualities $Q$ and wave functions for the vectormesons modelled accordingly. We verify the SVM-specific mechanism of formation of interacting gluonic strings between the quark constituents.

Comments: 355 pages. Doctoral dissertation in German. LaTeX2e, BibTeX; loading 70 eps/ps figures and 27 tables