{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/80931"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/80931","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"Search for t¯t Resonances in Dilepton Channel at the CMS Data Using Polarization Information","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Kilcoyne, Bahareh; 0000-0002-0773-7182"],"institution":"State University of New York at Buffalo","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Iashvili, Ia","Physics"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-10-29T16:48:15Z","date_published":"2019-10-29T16:48:15Z","updated_at":"2026-07-27T19:05:28Z","subjects":["particle physics"],"languages":["eng"],"rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10477/80931","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Iashvili, Ia","Physics"]},{"key":"dc:creator","label":"Author","values":["Kilcoyne, Bahareh; 0000-0002-0773-7182"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-10-29T16:48:15Z","2019","2019-08-08 17:29:50"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Text","Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["particle physics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/10477/80931"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","A search for heavy t¯t resonances is performed using the Large HadronCollider’s proton-proton collisions data collected by the Compact MuonSolenoid detector during year 2016. The analysis is optimized for eventswhere highly boosted top and anti-top quarks decay in dileptonic channel.Various kinematic variables are studied to achieve sensitivity for thesignal detection. No significant excess of events relative to the expectedyield from the Standard Model processes is observed. Upper limits onthe production cross section of heavy resonances decaying to a t¯t pairare calculated. We exclude Kaluza–Klein excitations of the gluon in theRandall–Sundrum and leptophobic topcolor Z’ models. Expected 95%CL upper limits on the production cross section obtained to be between3 × 10−2 - 20 pb for the resonance masses of 0.5 TeV to 5 TeV.To probe the signal mass region above these exclusions poses a challengeas we enter in the limited parton luminosity range of the LHC collisionsthat leads to decreasing search sensitivity to the signal when relying onlyon high momentum transfer variables for signal/background discrimination.To improve the signal/background discrimination, we identify andstudy variables that allow to regain sensitivity to high mass resonancesin the dilepton channel. We show using the top quark polarizationinformation through angular and energy variables provides additionalhandle to discriminate against the dominant SM t¯t production. Wefurther combine the polarization variables and kinematic variables inmultivariate approach to enhance sensitivity to the signal, particularlyfor the heavy mass resonances.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Search for t¯t Resonances in Dilepton Channel at the CMS Data Using Polarization Information"]}]}],"canonical_facts":{"dc:contributor":["Iashvili, Ia","Physics"],"dc:creator":["Kilcoyne, Bahareh; 0000-0002-0773-7182"],"dc:date":["2019-10-29T16:48:15Z","2019","2019-08-08 17:29:50"],"dc:description":["Ph.D.","A search for heavy t¯t resonances is performed using the Large HadronCollider’s proton-proton collisions data collected by the Compact MuonSolenoid detector during year 2016. The analysis is optimized for eventswhere highly boosted top and anti-top quarks decay in dileptonic channel.Various kinematic variables are studied to achieve sensitivity for thesignal detection. No significant excess of events relative to the expectedyield from the Standard Model processes is observed. Upper limits onthe production cross section of heavy resonances decaying to a t¯t pairare calculated. We exclude Kaluza–Klein excitations of the gluon in theRandall–Sundrum and leptophobic topcolor Z’ models. Expected 95%CL upper limits on the production cross section obtained to be between3 × 10−2 - 20 pb for the resonance masses of 0.5 TeV to 5 TeV.To probe the signal mass region above these exclusions poses a challengeas we enter in the limited parton luminosity range of the LHC collisionsthat leads to decreasing search sensitivity to the signal when relying onlyon high momentum transfer variables for signal/background discrimination.To improve the signal/background discrimination, we identify andstudy variables that allow to regain sensitivity to high mass resonancesin the dilepton channel. We show using the top quark polarizationinformation through angular and energy variables provides additionalhandle to discriminate against the dominant SM t¯t production. Wefurther combine the polarization variables and kinematic variables inmultivariate approach to enhance sensitivity to the signal, particularlyfor the heavy mass resonances.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/80931"],"dc:language":["eng"],"dc:publisher":["State University of New York at Buffalo"],"dc:rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"dc:subject":["particle physics"],"dc:title":["Search for t¯t Resonances in Dilepton Channel at the CMS Data Using Polarization Information"],"dc:type":["Text","Dissertation"]},"updated_at":"2026-07-27T19:05:28Z"}