# Measurement of the Ratio σtt̅ /σZ/γ*→ll and Precise Extraction of the tt̅ Cross Section

http://hdl.handle.net/10138/24120

#### Citation

Aaltonen , T , Mehtälä , P , Orava , R , Saarikko , H , Österberg , K & CDF Collaboration 2010 , ' Measurement of the Ratio σtt̅ /σZ/γ*→ll and Precise Extraction of the tt̅ Cross Section ' , Physical Review Letters , vol 105 , no. 1 , pp. 012001 .

 Title: Measurement of the Ratio σtt̅ /σZ/γ*→ll and Precise Extraction of the tt̅ Cross Section Author: Aaltonen, Timo; Mehtälä, Petteri; Orava, Risto; Saarikko, Heimo; Österberg, Kenneth; CDF Collaboration Contributor: University of Helsinki, Department of PhysicsUniversity of Helsinki, Helsinki Institute of PhysicsUniversity of Helsinki, Department of PhysicsUniversity of Helsinki, Department of PhysicsUniversity of Helsinki, Department of Physics Belongs to series: Physical Review Letters ISSN: 0031-9007 Abstract: We report a measurement of the ratio of the tt̅ to Z/γ* production cross sections in √s=1.96  TeV pp̅ collisions using data corresponding to an integrated luminosity of up to 4.6  fb-1, collected by the CDF II detector. The tt̅ cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/γ*→ll cross section predicted by the standard model, the extracted tt̅ cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result σtt̅ =7.70±0.52  pb, for a top-quark mass of 172.5  GeV/c2.We report a measurement of the ratio of the top-antitop to Z/gamma* production cross sections in sqrt(s) = 1.96 TeV proton-antiproton collisions using data corresponding to an integrated luminosity of up to 4.6 fb-1, collected by the CDF II detector. The top-antitop cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/gamma*->ll cross section, the extracted top-antitop cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result sigma_(top-antitop) = 7.70 +/- 0.52 pb, for a top-quark mass of 172.5 GeV/c^2. Peer review status: Peer reviewed URI: http://hdl.handle.net/10138/24120 Date: 2010 Subject: 114 Physical sciences
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