1999/03/05 by Andreas K. Freund, Andreas Freund, Freund, Andreas
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9903266
PhD Thesis, 168 pages, 39 figures, uses praca.sty, updated version (typos, small LaTex errors, figures etc.) as compared to available hard copy
arxiv created 1999/03/05 · openalex publication_date 1999/03/05 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In the first chapter we give an introduction to hard diffractive scattering in QCD to introduce basic concepts and terminology. In the second chapter we make predictions for the evolution of skewed parton distributions in a proton in the LLA. We calculate the DGLAP-type evolution kernels in the LLA and solve the skewed GLAP evolution equations with a modified version of the CTEQ-package. In the third chapter, we discuss the algorithms used in the LO evolution program for skewed parton distributions in the DGLAP region, discuss the stability of the code and reproduce the LO diagonal evolution within less than 0.5% of the original CTEQ-code. In chapter 4, we show that factorization holds for the deeply virtual Compton scattering amplitude in QCD, up to power suppressed terms, to all orders in perturbation theory. In chapter 5, we demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive, exclusive production of photons (DVCS) at large Q2 at HERA, while the aligned jet model allows one to estimate the cross section for intermediate Q2 ∼ 2 GeV2. We find a significant DVCS counting rate for the current generation of experiments at HERA and a large azimuthal angle asymmetry for HERA kinematics. In the last chapter, we propose a new methodology of gaining shape fits to skewed parton distributions and, for the first time, to determine the ratio of the real to imaginary part of the DIS amplitude. We do this by using several recent fits to F2(x,Q2) to compute the asymmetry A for the combined DVCS and Bethe-Heitler cross section. In the appendix, we give an application of distributional methods as discussed abstractly in chapter 4.