{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:50584"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:50584","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"W-pair production near threshold in unstable particle effective theory","abstract":"In this thesis we present a dedicated study of the four-fermion production process e- e+ ---> mu- nubar_mu u dbar X near the W-pair production threshold, in view of its importance for a precise determination of the W-boson mass at the ILC. The calculation is performed in the framework of unstable-particle effective theory, which allows for a gauge-invariant inclusion of instability effects, and for a systematic approximation of the full cross section with an expansion in the coupling constants, the ratio Gamma_W/M_W, and the non relativistic velocity v of the W boson. The effective-theory result, computed to next-to-leading order in the expansion parameters Gamma_W/M_W ~ alpha_ew ~ v^2, is compared to the full numerical next-to-leading order calculation of the four-fermion production cross section, and agreement to better than 0.5 % is found in the region of validity of the effective theory. Furthermore, we estimate the contributions of missing higher-order corrections to the four-fermion process, and how they translate into an error on the W-boson mass determination. We find that the dominant theoretical uncertainty on M_W is currently due to an incomplete treatment of initial-state radiation, while the remaining combined uncertainty of the two NLO calculations translates into dM_W ~ 5 MeV. The latter error is removed by an explicit computation of the dominant missing terms, which originate from the expansion in v of next-to-next-to leading order Standard Model diagrams. The effect of resummation of logarithmically enhanced terms is also investigated, but found to be negligible.","abstract_html":"In this thesis we present a dedicated study of the four-fermion production process e- e+ ---> mu- nubar_mu u dbar X near the W-pair production threshold, in view of its importance for a precise determination of the W-boson mass at the ILC. The calculation is performed in the framework of unstable-particle effective theory, which allows for a gauge-invariant inclusion of instability effects, and for a systematic approximation of the full cross section with an expansion in the coupling constants, the ratio Gamma_W/M_W, and the non relativistic velocity v of the W boson. The effective-theory result, computed to next-to-leading order in the expansion parameters Gamma_W/M_W ~ alpha_ew ~ v^2, is compared to the full numerical next-to-leading order calculation of the four-fermion production cross section, and agreement to better than 0.5 % is found in the region of validity of the effective theory. Furthermore, we estimate the contributions of missing higher-order corrections to the four-fermion process, and how they translate into an error on the W-boson mass determination. We find that the dominant theoretical uncertainty on M_W is currently due to an incomplete treatment of initial-state radiation, while the remaining combined uncertainty of the two NLO calculations translates into dM_W ~ 5 MeV. The latter error is removed by an explicit computation of the dominant missing terms, which originate from the expansion in v of next-to-next-to leading order Standard Model diagrams. The effect of resummation of logarithmically enhanced terms is also investigated, but found to be negligible.","abstract_has_math":false,"creators":["Falgari, Pietro"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Beneke, Martin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2008,"date_issued":"2008","date_published":"2008","updated_at":"2026-07-30T19:40:25Z","subjects":["info:eu-repo/classification/ddc/530","Elementarteilchenphysik","Physik","particle physics phaenomenology","effective theories","unstable particles","W bosons"],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113124%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113124%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113124%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/50584","outbound_label":"Repository record","outbound_source":"dc:identifier"},"source_record":{"url":"https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50584","prefix":"oai_dc"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Beneke, Martin"]},{"key":"dc:creator","label":"Author","values":["Falgari, Pietro"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2008"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-26820"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/530","Elementarteilchenphysik","Physik","particle physics phaenomenology","effective theories","unstable particles","W bosons"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/50584","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113124%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this thesis we present a dedicated study of the four-fermion production process e- e+ ---> mu- nubar_mu u dbar X near the W-pair production threshold, in view of its importance for a precise determination of the W-boson mass at the ILC. The calculation is performed in the framework of unstable-particle effective theory, which allows for a gauge-invariant inclusion of instability effects, and for a systematic approximation of the full cross section with an expansion in the coupling constants, the ratio Gamma_W/M_W, and the non relativistic velocity v of the W boson. The effective-theory result, computed to next-to-leading order in the expansion parameters Gamma_W/M_W ~ alpha_ew ~ v^2, is compared to the full numerical next-to-leading order calculation of the four-fermion production cross section, and agreement to better than 0.5 % is found in the region of validity of the effective theory. Furthermore, we estimate the contributions of missing higher-order corrections to the four-fermion process, and how they translate into an error on the W-boson mass determination. We find that the dominant theoretical uncertainty on M_W is currently due to an incomplete treatment of initial-state radiation, while the remaining combined uncertainty of the two NLO calculations translates into dM_W ~ 5 MeV. The latter error is removed by an explicit computation of the dominant missing terms, which originate from the expansion in v of next-to-next-to leading order Standard Model diagrams. The effect of resummation of logarithmically enhanced terms is also investigated, but found to be negligible."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University VI, 201 S. : graph. Darst. (2008). = Aachen, Techn. Hochsch., Diss., 2008"]},{"key":"dc:title","label":"Title","values":["W-pair production near threshold in unstable particle effective theory"]}]}],"canonical_facts":{"dc:contributor":["Beneke, Martin"],"dc:coverage":["DE"],"dc:creator":["Falgari, Pietro"],"dc:date":["2008"],"dc:description":["In this thesis we present a dedicated study of the four-fermion production process e- e+ ---> mu- nubar_mu u dbar X near the W-pair production threshold, in view of its importance for a precise determination of the W-boson mass at the ILC. The calculation is performed in the framework of unstable-particle effective theory, which allows for a gauge-invariant inclusion of instability effects, and for a systematic approximation of the full cross section with an expansion in the coupling constants, the ratio Gamma_W/M_W, and the non relativistic velocity v of the W boson. The effective-theory result, computed to next-to-leading order in the expansion parameters Gamma_W/M_W ~ alpha_ew ~ v^2, is compared to the full numerical next-to-leading order calculation of the four-fermion production cross section, and agreement to better than 0.5 % is found in the region of validity of the effective theory. Furthermore, we estimate the contributions of missing higher-order corrections to the four-fermion process, and how they translate into an error on the W-boson mass determination. We find that the dominant theoretical uncertainty on M_W is currently due to an incomplete treatment of initial-state radiation, while the remaining combined uncertainty of the two NLO calculations translates into dM_W ~ 5 MeV. The latter error is removed by an explicit computation of the dominant missing terms, which originate from the expansion in v of next-to-next-to leading order Standard Model diagrams. The effect of resummation of logarithmically enhanced terms is also investigated, but found to be negligible."],"dc:identifier":["https://publications.rwth-aachen.de/record/50584","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113124%22"],"dc:language":["eng"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-26820"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University VI, 201 S. : graph. Darst. (2008). = Aachen, Techn. Hochsch., Diss., 2008"],"dc:subject":["info:eu-repo/classification/ddc/530","Elementarteilchenphysik","Physik","particle physics phaenomenology","effective theories","unstable particles","W bosons"],"dc:title":["W-pair production near threshold in unstable particle effective theory"],"dc:type":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]},"updated_at":"2026-07-30T19:40:25Z"}