Measurement of the tt cross section in pp collisions at {radical}(s)=1.96 TeV using dilepton events with a lepton plus track selection

Journal Article · Mon Jun 01 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.79.112007· OSTI ID:21296415

Aaltonen, T; Maki, T; Mehtala, P; Orava, R; Osterberg, K; Saarikko, H; van Remortel, N ^[1]; Adelman, J; Brubaker, E; Fedorko, W T; Grosso-Pilcher, C; Ketchum, W; Kim, Y K; Krop, D; Kwang, S; Lee, H S; Paramonov, A A; Schmidt, M A; Shiraishi, S; Shochet, M ^[2]

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1. Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki (Finland)
2. Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States)

This paper reports a measurement of the cross section for the pair production of top quarks in pp collisions at {radical}(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{sup -1}. The cross section is measured in the dilepton channel, the subset of tt events in which both top quarks decay through t{yields}Wb{yields}l{nu}b, where l=e, {mu}, or {tau}. 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 tt acceptance, particularly for the case in which one W decays as W{yields}{tau}{nu}. 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 {sigma}{sub tt}=9.6{+-}1.2(stat){sub -0.5}{sup +0.6}(sys){+-}0.6(lum) pb, assuming a branching ratio of BR(W{yields}l{nu})=10.8% and a top mass of m{sub t}=175 GeV/c{sup 2}.

• OSTI ID: 21296415
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 79; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BRANCHING RATIO
CROSS SECTIONS
ELECTRONS
FERMILAB COLLIDER DETECTOR
FERMILAB TEVATRON
LEPTONS
LUMINOSITY
MASS
MUONS
PAIR PRODUCTION
PARTICLE DECAY
PARTICLE TRACKS
PROTON-PROTON INTERACTIONS
T QUARKS
TEV RANGE 01-10