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Analytic Evolution Of Singular Distribution Amplitudes In Qcd, Asli Tandogan
Analytic Evolution Of Singular Distribution Amplitudes In Qcd, Asli Tandogan
Physics Theses & Dissertations
Distribution amplitudes (DAs) are the basic functions that contain information about the quark momentum. DAs are necessary to describe hard exclusive processes in quantum chromodynamics. We describe a method of analytic evolution of DAs that have singularities such as nonzero values at the end points of the support region, jumps at some points inside the support region and cusps. We illustrate the method by applying it to the evolution of a flat (constant) DA, antisymmetric flat DA, and then use the method for evolution of the two-photon generalized distribution amplitude. Our approach to DA evolution has advantages over the standard …
Inclusive And Exclusive Compton Processes In Quantum Chromodynamics, A. Psaker
Inclusive And Exclusive Compton Processes In Quantum Chromodynamics, A. Psaker
Physics Theses & Dissertations
In our work, we describe two types of Compton processes. As an example of an inclusive process, we consider the high-energy photoproduction of massive muon pairs off the nucleon. We analyze the process in the framework of the QCD parton model, in which the usual parton distributions emerge as a tool to describe the nucleon in terms of quark and gluonic degrees of freedom. To study its exclusive version, a new class of phenomenological functions is required, namely, generalized parton distributions. They can be considered as a generalization of the usual parton distributions measured in deeply inelastic lepton-nucleon scattering. Generalized …
Generalized Compton Amplitudes In Quantum Chromodynamics, Ignati Grigentch
Generalized Compton Amplitudes In Quantum Chromodynamics, Ignati Grigentch
Physics Theses & Dissertations
In this dissertation we describe results of our studies of generalized Compton amplitudes. We have calculated the one-loop corrections to the amplitude in the coordinate representation in terms of nonlocal string light-ray operators. We have also developed a consistent approach to the problem of constructing the gauge invariant Compton amplitude and obtained an expression for the explicitly gauge invariant amplitude which includes all the generalized target-mass corrections.
Virtual Compton Scattering Processes In Quantum Chromodynamics, Igor V. Musatov
Virtual Compton Scattering Processes In Quantum Chromodynamics, Igor V. Musatov
Physics Theses & Dissertations
Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual Parton distributions for the case when long-distance information is accumulated in nonforward matrix elements [special characters omitted] of quark and gluon light-cone operators. We consider different aspects of the investigation of the virtual Compton amplitude in the QCD on two examples: the spin dependent observables in the forward virtual Compton process (measured in the experiments on deep inelastic scattering) and the γγ* transition form factor. Then we discuss in detail evolution equations for non-forward parton distributions [special characters omitted] The …