Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection
This paper reports a measurement of the cross section for the pair production of top quarks in pp̅ collisions at √s=1.96 TeV at the Fermilab Tevatron. The data were collected from the CDF run II detector in a set of runs with a total integrated luminosity of 1.1 fb[superscript -1]. The cross sect...
| Main Authors: | , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Physical Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/51886 https://orcid.org/0000-0002-6047-4211 |
| _version_ | 1826214296176033792 |
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| author | Xie, Si Knuteson, Bruce O. Henderson, C. Hahn, Kristian Allan Gomez-Ceballos, Guillelmo Choudalakis, Georgios Paus, Christoph M. E. Goncharov, Maxim Bauer, Gerry P Makhoul, Khaldoun |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Xie, Si Knuteson, Bruce O. Henderson, C. Hahn, Kristian Allan Gomez-Ceballos, Guillelmo Choudalakis, Georgios Paus, Christoph M. E. Goncharov, Maxim Bauer, Gerry P Makhoul, Khaldoun |
| author_sort | Xie, Si |
| collection | MIT |
| description | This paper reports a measurement of the cross section for the pair production of top quarks in pp̅ collisions at √s=1.96 TeV at the Fermilab Tevatron. The data were collected from the CDF run II detector in a set of runs with a total integrated luminosity of 1.1 fb[superscript -1]. The cross section is measured in the dilepton channel, the subset of tt̅ events in which both top quarks decay through t→Wb→ℓνb, where ℓ=e, μ, or τ. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the tt̅ acceptance, particularly for the case in which one W decays as W→τν. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified b jet. We present the results of measurements performed with and without the request of an identified b jet. The former is the first published CDF result for which a b-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag lepton+track candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged subsamples, and a combined cross section is calculated by maximizing a likelihood. The result is σ[subscript tt̅] =9.6±1.2(stat)[subscript -0.5][superscript +0.6](sys)±0.6(lum) pb, assuming a branching ratio of BR(W→ℓν)=10.8% and a top mass of mt=175 GeV/c[superscript 2]. |
| first_indexed | 2024-09-23T16:03:18Z |
| format | Article |
| id | mit-1721.1/51886 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:03:18Z |
| publishDate | 2010 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/518862023-02-26T04:12:02Z Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection Measurement of the tt̅ cross section in pp̅ collisions at √s=1.96 TeV using dilepton events with a lepton plus track selection Xie, Si Knuteson, Bruce O. Henderson, C. Hahn, Kristian Allan Gomez-Ceballos, Guillelmo Choudalakis, Georgios Paus, Christoph M. E. Goncharov, Maxim Bauer, Gerry P Makhoul, Khaldoun Massachusetts Institute of Technology. Department of Physics Massachusetts Institute of Technology. Laboratory for Nuclear Science Paus, Christoph M. E. Xie, Si Makhoul, K. Knuteson, Bruce O. Henderson, C. Hahn, Kristian Allan Goncharov, M. Gomez-Ceballos, Guillelmo Choudalakis, Georgios Bauer, Gerry P. Paus, Christoph M. E. This paper reports a measurement of the cross section for the pair production of top quarks in pp̅ collisions at √s=1.96 TeV at the Fermilab Tevatron. The data were collected from the CDF run II detector in a set of runs with a total integrated luminosity of 1.1 fb[superscript -1]. The cross section is measured in the dilepton channel, the subset of tt̅ events in which both top quarks decay through t→Wb→ℓνb, where ℓ=e, μ, or τ. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the tt̅ acceptance, particularly for the case in which one W decays as W→τν. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified b jet. We present the results of measurements performed with and without the request of an identified b jet. The former is the first published CDF result for which a b-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag lepton+track candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged subsamples, and a combined cross section is calculated by maximizing a likelihood. The result is σ[subscript tt̅] =9.6±1.2(stat)[subscript -0.5][superscript +0.6](sys)±0.6(lum) pb, assuming a branching ratio of BR(W→ℓν)=10.8% and a top mass of mt=175 GeV/c[superscript 2]. Academy of Finland Slovak R&D Agency Programa Consolider-Ingenio 2010, Spain Ministerio de Ciencia e Innovación, Spain Russian Foundation for Basic Research Institut National de Physique Nucleaire et Physique des Particules/CNRS Royal Society, United Kingdom Science and Technology Facilities Council, United Kingdom Korean Research Foundation Korean Science and Engineering Foundation Bundesministerium für Bildung und Forschung, Germany Alfred P. Sloan Foundation Swiss National Science Foundation National Science Council of the Republic of China Natural Sciences and Engineering Research Council of Canada Ministry of Education, Culture, Sports, Science and Technology of Japan Italian Istituto Nazionale di Fisica Nucleare National Science Foundation United States Department of Energy 2010-03-02T18:02:39Z 2010-03-02T18:02:39Z 2009-06 2009-03 Article http://purl.org/eprint/type/JournalArticle 1550-2368 1550-7998 http://hdl.handle.net/1721.1/51886 CDF Collaboration et al. “Measurement of the tt-bar cross section in pp-bar collisions at s=1.96 TeV using dilepton events with a lepton plus track selection.” Physical Review D 79.11 (2009): 112007. © 2009 The American Physical Society https://orcid.org/0000-0002-6047-4211 en_US http://dx.doi.org/10.1103/PhysRevD.79.112007 Physical Review D Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Xie, Si Knuteson, Bruce O. Henderson, C. Hahn, Kristian Allan Gomez-Ceballos, Guillelmo Choudalakis, Georgios Paus, Christoph M. E. Goncharov, Maxim Bauer, Gerry P Makhoul, Khaldoun Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title | Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title_full | Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title_fullStr | Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title_full_unstemmed | Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title_short | Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection |
| title_sort | measurement of the tt bar cross section in pp bar collisions at sqrt s 1 96 tev using dilepton events with a lepton plus track selection |
| url | http://hdl.handle.net/1721.1/51886 https://orcid.org/0000-0002-6047-4211 |
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