A measurement of the production cross sections of top quark pairs in association with a W or Z boson is presented. The measurement uses 20.3 fb−1 of data from proton-proton collisions at √s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. Four different final states are considered: two opposite-sign leptons, two same-sign leptons, three leptons, and four leptons. The t t̅ W and t t̅ Z cross sections are simultaneously extracted using a maximum likelihood fit over all the final states. The t t̅ Z cross section is measured to be 176+58−52 fb, corresponding to a signal significance of 4.2σ. The t t̅ W cross section is measured to be 369+100−91 fb, corresponding to a signal significance of 5.0σ. The results are consistent with next-to-leading-order calculations for the tt̅W and tt̅Z processes.
","abstract_html":"<p>A measurement of the production cross sections of top quark pairs in association with a W or Z boson is presented. The measurement uses 20.3 fb−1 of data from proton-proton collisions at √s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. Four different final states are considered: two opposite-sign leptons, two same-sign leptons, three leptons, and four leptons. The t t̅ W and t t̅ Z cross sections are simultaneously extracted using a maximum likelihood fit over all the final states. The t t̅ Z cross section is measured to be 176+58−52 fb, corresponding to a signal significance of 4.2σ. The t t̅ W cross section is measured to be 369+100−91 fb, corresponding to a signal significance of 5.0σ. The results are consistent with next-to-leading-order calculations for the tt̅W and tt̅Z processes.</p>","abstract_has_math":false,"creators":["Zhou, Chen"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Kruse, Mark"],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016","date_published":"2016","updated_at":"2026-07-24T02:07:12Z","subjects":["Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10161/12245","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Kruse, Mark"]},{"key":"dc:creator","label":"Author","values":["Zhou, Chen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-06-06T16:11:58Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-06-06T16:11:58Z"]},{"key":"dc:date.issued","label":"Date","values":["2016"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10161/12245"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A measurement of the production cross sections of top quark pairs in association with a W or Z boson is presented. The measurement uses 20.3 fb−1 of data from proton-proton collisions at √s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. Four different final states are considered: two opposite-sign leptons, two same-sign leptons, three leptons, and four leptons. The t t̅ W and t t̅ Z cross sections are simultaneously extracted using a maximum likelihood fit over all the final states. The t t̅ Z cross section is measured to be 176+58−52 fb, corresponding to a signal significance of 4.2σ. The t t̅ W cross section is measured to be 369+100−91 fb, corresponding to a signal significance of 5.0σ. The results are consistent with next-to-leading-order calculations for the tt̅W and tt̅Z processes.
"]},{"key":"dc:title","label":"Title","values":["Measurement of the tt̅W and tt̅Z Cross Sections using Proton-Proton Collisions at √s = 8 TeV with the ATLAS Detector"]}]}],"canonical_facts":{"dc:contributor.advisor":["Kruse, Mark"],"dc:creator":["Zhou, Chen"],"dc:date.accessioned":["2016-06-06T16:11:58Z"],"dc:date.available":["2016-06-06T16:11:58Z"],"dc:date.issued":["2016"],"dc:description.abstract":["A measurement of the production cross sections of top quark pairs in association with a W or Z boson is presented. The measurement uses 20.3 fb−1 of data from proton-proton collisions at √s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. Four different final states are considered: two opposite-sign leptons, two same-sign leptons, three leptons, and four leptons. The t t̅ W and t t̅ Z cross sections are simultaneously extracted using a maximum likelihood fit over all the final states. The t t̅ Z cross section is measured to be 176+58−52 fb, corresponding to a signal significance of 4.2σ. The t t̅ W cross section is measured to be 369+100−91 fb, corresponding to a signal significance of 5.0σ. The results are consistent with next-to-leading-order calculations for the tt̅W and tt̅Z processes.
"],"dc:identifier.uri":["https://hdl.handle.net/10161/12245"],"dc:subject":["Physics"],"dc:title":["Measurement of the tt̅W and tt̅Z Cross Sections using Proton-Proton Collisions at √s = 8 TeV with the ATLAS Detector"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T02:07:12Z"}