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AbstractAbstract
[en] In this thesis, we have discussed several aspects of the pion structure that are accessible with lattice QCD. In our introduction, we briefly mentioned QCD phenomenology for the pion that is obtained from experiments, namely the electromagnetic form factor connected to the charge radius, and the parton distribution functions (PDFs) which provide probabilities of finding a parton with a certain momentum fraction. These are embedded in the more general framework of generalised parton distributions (GPDs) which from the basis of this work. Special attention was paid to Mellin moments of GPDs that are parametrised in generalised form factors relevant for lattice calculations. The two subsequent Chapters were devoted to an introduction to lattice QCD and the lattice techniques we used. Here we started from the QCD Lagrangian and the path integral, to then explain our lattice gauge and fermion action, both going back to Wilson. For the latter we used the clover improved version for our dynamical two flavour simulations. We then gave details of the calculation of two- and three-point functions on the lattice, as well as the operators involved and how the matrix elements are extracted from the lattice data by building suitable ratios. The pion form factor was used for an exhaustive explanation of our methods to analyse the data. We investigated the momentum dependence of the form factor and its extrapolation to physical pion masses. We also payed attention to the lattice artifacts appearing in any lattice simulation. We also tried to estimate the size of finite volume corrections. We applied the established methods to the analysis of higher moments of the forward distributions and the second moment of the non-forward case. Finally, we gave an outlook on the densities of polarised quarks in the pion. (orig.)
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Source
May 2007; 116 p; ISSN 1435-8085;
; Diss. (Dr.rer.nat.)

Record Type
Report
Literature Type
Thesis/Dissertation
Report Number
Country of publication
BOSONS, COMPOSITE MODELS, CONSTRUCTIVE FIELD THEORY, DIMENSIONLESS NUMBERS, ELEMENTARY PARTICLES, FERMIONS, FIELD THEORIES, FORM FACTORS, FUNCTIONS, HADRONS, INTEGRAL TRANSFORMATIONS, INTEGRALS, MATHEMATICAL MODELS, MATHEMATICAL OPERATORS, MATHEMATICAL SOLUTIONS, MESONS, NUMERICAL SOLUTION, ORIENTATION, PARTICLE MODELS, PARTICLE PROPERTIES, PATH INTEGRALS, PSEUDOSCALAR MESONS, QUANTUM FIELD THEORY, QUARK MODEL, SIMULATION, TRANSFORMATIONS
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