No description available.

The analysis of hadronic events in high-energy electron-positron annihilation often relies upon the clustering of individual hadrons into energetic jets. By solving our theory of strong interactions, Quantum Chromodynamics (QCD) perturbatively, we may make theoretical predictions for these multijet configurations. In this thesis we provide some calculational tools which are useful for evaluating terms in the perturbative series beyond leading order. These include a convenient method of dealing with one-loop integrals containing tensor denominators and universal factorization formulae for matrix elements where two particles are unresolved, which are relevant at the 2-loop (next-to-next-to-leading order) level. In particular we concentrate on the case of the next-to-leading order corrections to 4 jet production (and related processes) and apply . our techniques to obtain explicit results in electron-positron annihilation which are then compared with experimental data.

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / In this thesis we present a comprehensive study of perturbative and non-perturbative non-Abelian gauge theories in the light of gauge-fixing procedures, focusing our attention on the BRST formalism in Yang-Mills theory. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1284180 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / In this thesis we present a comprehensive study of perturbative and non-perturbative non-Abelian gauge theories in the light of gauge-fixing procedures, focusing our attention on the BRST formalism in Yang-Mills theory. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1284180 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2007

Thesis (Ph.D.)--Tufts University, 1990. / Adviser: Gary R. Goldstein. Submitted to the Dept. of Physics. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2002. / Bibliography: leaves 124-127.

Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, Discipline of Physics, 2004. / Bibliography: p. 222-229.

Thesis (Ph.D.) --University of Adelaide, School of Chemistry and Physics, Discipline of Physics, 2006. / "5 April 2006" Bibliography: pages 147-150. Also available in print form.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 163-169).

Made available in DSpace on 2018-07-27T18:26:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-16. Added 1 bitstream(s) on 2018-07-27T18:30:43Z : No. of bitstreams: 1 000875923.pdf: 1054863 bytes, checksum: 3bb8e98d1fc3ff8911eda249455d642f (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A presente tese é baseada em parte do trabalho realizado durante o Doutorado e diz respeito aos dois domínios da Cromodinâmica Quântica (QCD) a temperatura zero: o regime confinado, a baixas energias, e o assintoticamente livre, a altas energias. Com o objetivo de cumprir uma ponte entre estes domínios e inspirado em sugestões de aprimoramentos da série perturbativa, este trabalho investiga uma proposta para uma expansão perturbativa aprimorada, a ser um método aplicável tanto à fenomenologia da QCD quanto a estudos de seu regime não-perturbativo. A proposta consiste numa expansão em loops efetivos - um híıbrido entre equações de Schwinger-Dyson e expansão em loops usual, fazendo uso de ferramentas desta porém vestindo certas quantidades como forma de considerar seu comportamento completo dentro de loops. A tese descreve os principais avanços nesse sentido, na aplicação a funções de correlação - em particular os propagadores do gluon e do ghost, como um passo preliminar a futuras aplicações. Após lidar com questões de transversalidade do propagador do gluon e renormalizabilidade no método, a expansão em loops efetivos na sua presente forma contém gluons (dinamicamente) massivos e uma carga efetiva, além da possiblidade de uma vestimenta para o vértice de três gluons. Nesta formulação, foram obtidos resultados qualitativos razoáveis para o comportamento não-perturbativo completo dos propagadores do ghost e do gluon, e comparação com a rede é analisada. Perspectivas de curto e de mais longo prazo são discutidas / This thesis is based on part of the work done during the Ph.D., and it concerns the two distinguished domains of Quantum Chromodynamics (QCD) at zero temperature: the low-energy, confined domain, and the high-energy, asymptotically free one. Aiming to bridge the gap between them, and inspired by suggested improvements of the QCD perturbative series, this work investigates a proposal for an improved perturbative expansion, as a method to be applicable to QCD phenomenology, as well as to nonperturbative studies. The proposal consists in an effective-loop expansion - a hybrid between Schwinger- Dyson equations and usual loop expansions, making use of the latter's framework, yet dressing certain quantities in order to account for their complete behavior inside loops. The thesis describes the main efforts on this matter, in its application to correlation functions - the gluon and ghost propagators, in particular, as a preliminary step preceding further applications. After dealing with issues as transversality of the gluon self-energy and renormalizability within the method, the present form of the effective-loop expansion contains dynamically massive gluons and an effective running charge, besides the possible dressing of the three-gluon vertex. Within this formulation, reasonable qualitative results were obtained for achieving the complete, nonperturbative behavior of the ghost and gluon propagators, and comparison with lattice is analyzed. Readily achievable and longer term prospects are also discussed / FAPESP: 2011/10889-0