Measurement of sigma(proton-antiproton decaying to top quark-antitop quark) in the tau + jets channel by the D0 experiment at run II of the tevatron collider
Ph.D. (Doctor of Philosophy)
Department of Physics
Particles (Nuclear physics)
The top quark is the heaviest and most mysterious of the known elementary particles. Therefore, careful study of its production rate and other properties is of utmost importance for modern particle physics. The Tevatron is the only facility currently capable of studying top quark properties by on-shell production. Measurement of the top quark pair production cross section is one of the major goals of the Tevatron Run II physics program. It provides an excellent test of QCD at energies exceeding 100 GeV. We report on a new measurement of pp̅ ⟶ tt̅ production at √s = 1.96 TeV using 350 pb⁻¹ of data collected with the DØ detector between 2002 and 2005. We focus on the final state where a W boson from one of the top quarks decays into a τ lepton and its associated neutrino, while the other decays into a quark-antiquark pair. We aim to select those events in which the τ lepton subsequently decays to one or three charged hadrons, zero or more neutral hadrons and a tau neutrino (the charge conjugate processes are implied in all of the above). The observable signature thus consists of a narrow calorimeter shower with associated track(s) characteristic of a hadronic tau decay, four or more jets, of which two are initiated by b quarks accompanying the W's in the top quark decays, and a large net missing momentum in the transverse plane due to the energetic neutrino-antineutrino pair that leave no trace in the detector media. The preliminary result for the measured cross section is: [special characters omitted]
Arov, Mikhail, "Measurement of σ(pp̅ ⟶ tt̅) in the τ + jets channel by the DØ experiment at run II of the tevatron collider" (2008). Graduate Research Theses & Dissertations. 3917.
xvi, 117 pages
Northern Illinois University
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