{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:60492"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:60492","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Bestimmung der b-Quarkmasse an der Z-Massenskala","abstract":"In hadronic decays of the Z boson recorded in 1994 with the OPAL detector at LEP b quark events were selected using the long lifetime of b flavoured hadrons. Different observables for the determination of the b quark mass were studied. Jetrates were found to be best suited. The 3-jet rates in b quark events for seven different jetfinder were compared to the 3-jet rate in light quark events, and a clear deviation from unity was found. A combination of all seven individual jet finders yielded for the $MS$ mass mb(mz) = ( 2.67 pm 0.03 (stat.) +0.29 -0.37 (syst.) pm 0.19 (theo.) GeV The running of the b quark mass as predicted by QCD is confirmed and together with the value estimated at the scale of the production threshold of mb(PDG,mb)=(4.2 pm 0.2) GeV , a constant mass in the MSbar scheme is ruled out by 3.9 standard deviations. The main contributions to the total uncertainty come from the modelling of the b quark fragmentation and the simulation related to the b selection and the simulation of the detector in general.","abstract_html":"In hadronic decays of the Z boson recorded in 1994 with the OPAL detector at LEP b quark events were selected using the long lifetime of b flavoured hadrons. Different observables for the determination of the b quark mass were studied. Jetrates were found to be best suited. The 3-jet rates in b quark events for seven different jetfinder were compared to the 3-jet rate in light quark events, and a clear deviation from unity was found. A combination of all seven individual jet finders yielded for the $MS$ mass mb(mz) = ( 2.67 pm 0.03 (stat.) +0.29 -0.37 (syst.) pm 0.19 (theo.) GeV The running of the b quark mass as predicted by QCD is confirmed and together with the value estimated at the scale of the production threshold of mb(PDG,mb)=(4.2 pm 0.2) GeV , a constant mass in the MSbar scheme is ruled out by 3.9 standard deviations. The main contributions to the total uncertainty come from the modelling of the b quark fragmentation and the simulation related to the b selection and the simulation of the detector in general.","abstract_has_math":true,"creators":["Seuster, Rolf"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Bethke, Siegfried"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2001,"date_issued":"2001","date_published":"2001","updated_at":"2026-07-30T19:42:56Z","subjects":["info:eu-repo/classification/ddc/530","Physik","b-Quark","Masse","Z-Boson","Hadronischer Zerfall","Schweres Quark","Massenbestimmung"],"languages":["ger"],"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-122199%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122199%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122199%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/60492","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bethke, Siegfried"]},{"key":"dc:creator","label":"Author","values":["Seuster, Rolf"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2001"]},{"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-2667"]},{"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","Physik","b-Quark","Masse","Z-Boson","Hadronischer Zerfall","Schweres Quark","Massenbestimmung"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["ger"]},{"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/60492","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122199%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In hadronic decays of the Z boson recorded in 1994 with the OPAL detector at LEP b quark events were selected using the long lifetime of b flavoured hadrons. Different observables for the determination of the b quark mass were studied. Jetrates were found to be best suited. The 3-jet rates in b quark events for seven different jetfinder were compared to the 3-jet rate in light quark events, and a clear deviation from unity was found. A combination of all seven individual jet finders yielded for the $MS$ mass mb(mz) = ( 2.67 pm 0.03 (stat.) +0.29 -0.37 (syst.) pm 0.19 (theo.) GeV The running of the b quark mass as predicted by QCD is confirmed and together with the value estimated at the scale of the production threshold of mb(PDG,mb)=(4.2 pm 0.2) GeV , a constant mass in the MSbar scheme is ruled out by 3.9 standard deviations. The main contributions to the total uncertainty come from the modelling of the b quark fragmentation and the simulation related to the b selection and the simulation of the detector in general."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University 117 S. : Ill., graph. Darst. (2001). = Aachen, Techn. Hochsch., Diss., 2001"]},{"key":"dc:title","label":"Title","values":["Bestimmung der b-Quarkmasse an der Z-Massenskala"]}]}],"canonical_facts":{"dc:contributor":["Bethke, Siegfried"],"dc:coverage":["DE"],"dc:creator":["Seuster, Rolf"],"dc:date":["2001"],"dc:description":["In hadronic decays of the Z boson recorded in 1994 with the OPAL detector at LEP b quark events were selected using the long lifetime of b flavoured hadrons. Different observables for the determination of the b quark mass were studied. Jetrates were found to be best suited. The 3-jet rates in b quark events for seven different jetfinder were compared to the 3-jet rate in light quark events, and a clear deviation from unity was found. A combination of all seven individual jet finders yielded for the $MS$ mass mb(mz) = ( 2.67 pm 0.03 (stat.) +0.29 -0.37 (syst.) pm 0.19 (theo.) GeV The running of the b quark mass as predicted by QCD is confirmed and together with the value estimated at the scale of the production threshold of mb(PDG,mb)=(4.2 pm 0.2) GeV , a constant mass in the MSbar scheme is ruled out by 3.9 standard deviations. 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