We present a measurement of the top-quark width in the lepton+jets decay channel of tt̄ events produced in pp̄ collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to 4.3fb⊃-1 of integrated luminosity, we identify 756 candidate events. The top-quark mass and the mass of the hadronically decaying W boson that comes from the top-quark decay are reconstructed for each event and compared with templates of different top-quark widths (Γt) and deviations from nominal jet energy scale (ΔJES) to perform a simultaneous fit for both parameters, where ΔJES is used for the in situ calibration of the jet energy scale. By applying a Feldman-Cousins approach, we establish an upper limit at 95% confidence level (CL) of Γt<7.6GeV and a two-sided 68% CL interval of 0.3GeV<4.4GeV for a top-quark mass of 172.5GeV/c2, which are consistent with the standard model prediction. © 2010 The American Physical Society.

Direct top-quark width measurement at CDF

Piacentino G.;
2010-01-01

Abstract

We present a measurement of the top-quark width in the lepton+jets decay channel of tt̄ events produced in pp̄ collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to 4.3fb⊃-1 of integrated luminosity, we identify 756 candidate events. The top-quark mass and the mass of the hadronically decaying W boson that comes from the top-quark decay are reconstructed for each event and compared with templates of different top-quark widths (Γt) and deviations from nominal jet energy scale (ΔJES) to perform a simultaneous fit for both parameters, where ΔJES is used for the in situ calibration of the jet energy scale. By applying a Feldman-Cousins approach, we establish an upper limit at 95% confidence level (CL) of Γt<7.6GeV and a two-sided 68% CL interval of 0.3GeV<4.4GeV for a top-quark mass of 172.5GeV/c2, which are consistent with the standard model prediction. © 2010 The American Physical Society.
http://oai.aps.org/oai?verb=GetRecord&amp;Identifier=oai:aps.org:PhysRevLett.105.232003&amp;metadataPrefix=oai_apsmeta_2
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11695/88000
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