Abstract
We present a measurement of the top-quark width in the lepton+jets decay channel of tt events produced in pp collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to 4.3 fb{sup -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 ({Gamma}{sub t}) and deviations from nominal jet energy scale ({Delta}{sub JES}) to perform a simultaneous fit for both parameters, where {Delta}{sub JES} 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 {Gamma}{sub t}<7.6 GeV and a two-sided 68% CL interval of 0.3 GeV<{Gamma}{sub t}<4.4 GeV for a top-quark mass of 172.5 GeV/c{sup 2}, which are consistent with the standard model prediction.