Direct Top-Quark Width Measurement at CDF

Résumé fourni par la source

We present a measurement of the top-quark width in the $\mathrm{\text{lepton}}+\mathrm{\text{jets}}$ decay channel of $t\overline{t}$ events produced in $p\overline{p}$ collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to $4.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ 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 (${\ensuremath{\Gamma}}_{t}$) and deviations from nominal jet energy scale (${\ensuremath{\Delta}}_{\mathrm{JES}}$) to perform a simultaneous fit for both parameters, where ${\ensuremath{\Delta}}_{\mathrm{JES}}$ 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 ${\ensuremath{\Gamma}}_{t}<7.6\text{ }\text{ }\mathrm{GeV}$ and a two-sided 68% CL interval of $0.3\text{ }\text{ }\mathrm{GeV}<{\ensuremath{\Gamma}}_{t}<4.4\text{ }\text{ }\mathrm{GeV}$ for a top-quark mass of $172.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, which are consistent with the standard model prediction.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.