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dc.contributor.authorBuanes, Trygveeng
dc.contributor.authorBurgess, Thomaseng
dc.contributor.authorEigen, Geraldeng
dc.contributor.authorKastanas, Alexeng
dc.contributor.authorLiebig, Wolfgangeng
dc.contributor.authorLipniacka, Annaeng
dc.contributor.authorRosendahl, Peter Lundgaardeng
dc.contributor.authorSandaker, Heidieng
dc.contributor.authorSjursen, Therese B.eng
dc.contributor.authorStugu, Bjarneeng
dc.contributor.authorTonoyan, Arshakeng
dc.contributor.authorUgland, Mareneng
dc.contributor.authorBugge, Larseng
dc.contributor.authorBuran, Torleiveng
dc.contributor.authorCameron, David Gordoneng
dc.contributor.authorCzyczula, Zofiaeng
dc.contributor.authorGjelsten, Børge Kileeng
dc.contributor.authorGramstad, Eirikeng
dc.contributor.authorLund, Esbeneng
dc.contributor.authorOuld-Saada, Farideng
dc.contributor.authorPajchel, Katarinaeng
dc.contributor.authorPedersen, Maikeneng
dc.contributor.authorPylypchenko, Yuriyeng
dc.contributor.authorRead, Alexander Lincolneng
dc.contributor.authorRøhne, Ole Myreneng
dc.contributor.authorSmestad, Lillianeng
dc.contributor.authorStapnes, Steinareng
dc.contributor.authorStrandlie, Areeng
dc.contributor.authorAad, Georgeseng
dc.contributor.authorAbajyan, Tatevikeng
dc.contributor.authorAbbott, Bradeng
dc.contributor.authorAbdallah, Jalaleng
dc.contributor.authorAbdel Khalek, Samaheng
dc.contributor.authorAbdinov, Ovsat Bahram oglueng
dc.contributor.authorAben, Rosemarieeng
dc.contributor.authorAbi, Babakeng
dc.contributor.authorAbolins, Mariseng
dc.contributor.authorAbouZeid, Hasseng
dc.contributor.authorAbramowicz, Halinaeng
dc.contributor.authorAbreu, Hensoeng
dc.contributor.authorAcerbi, Emilioeng
dc.contributor.authorAdamczyk, Leszekeng
dc.contributor.authorAdams, Davideng
dc.contributor.authorAddy, Tetteh N.eng
dc.contributor.authorAdelman, Jareedeng
dc.contributor.authorAdomeit, Stefanieeng
dc.contributor.authorAdye, Timeng
dc.contributor.authorAefsky, Scott Alaneng
dc.contributor.authorAgatonovic-Jovin, Tatjanaeng
dc.contributor.authorAguilar Saavedra, Juan Antonioeng
dc.contributor.authorAharrouche, Mohamedeng
dc.contributor.authorATLAS, Collaborationeng
dc.date.accessioned2015-05-15T11:15:34Z
dc.date.available2015-05-15T11:15:34Z
dc.date.issued2014-04-21eng
dc.identifier.issn0556-2821eng
dc.identifier.urihttp://hdl.handle.net/1956/9881
dc.description.abstractUsing a sample of dilepton top-quark pair (tt¯) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of tt¯+b+X and tt¯+c+X, collectively referred to as tt¯ + HF. The data set used corresponds to an integrated luminosity of 4.7  fb−1 of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the tt¯ sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the tt¯ decays and the third to additional HF production. The dominant background to tt¯ + HF in this sample is tt¯+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in the sample is performed. The result of the fit shows that 79 ± 14 (stat) ± 22 (syst) of the 105 selected extra b-tagged jets originate from HF quarks, 3 standard deviations away from the hypothesis of zero tt¯ + HF production. The result for extra HF production is quoted as a ratio (RHF) of the cross section for tt¯ + HF production to the cross section for tt¯ production with at least one additional jet. Both cross sections are measured in a fiducial kinematic region within the ATLAS acceptance. RHF is measured to be [6.2±1.1(stat)±1.8(syst)]% for jets with pT>25  GeV and |η|<2.5, in agreement with the expectations from Monte Carlo generators.en_US
dc.language.isoengeng
dc.publisherAmerican Physical Societyeng
dc.rightsAttribution CC BYeng
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/eng
dc.titleStudy of heavy-flavor quarks produced in association with top-quark pairs at √s =7 TeV using the ATLAS detectoreng
dc.typeJournal articleeng
dc.subject.nsiVDP::Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431nob
dc.subject.nsiVDP::Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431eng
dc.date.updated2015-04-09T06:44:45Zen_US
dc.rights.holderCopyright 2014 CERN, for the ATLAS Collaboration
dc.type.versionpublishedVersioneng
bora.peerreviewedPeer reviewedeng
bora.journalTitlePhysical Review Deng
bibo.volume89eng
bibo.issue7eng
bibo.number72012eng
bibo.doihttp://dx.doi.org/10.1103/PhysRevD.89.072012eng
bora.accessRightsinfo:eu-repo/semantics/openAccesseng
dc.identifier.cristinID1149196eng
dc.identifier.doi10.1103/physrevd.89.072012


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