W boson polarization measurement in the ttbar dilepton channel using the CDF II Detector

Abstract

We present a measurement of $W$ boson polarization in top-quark decays in $t\bar{t}$ events with decays to dilepton final states using $5.1\mathrm{f}{\mathrm{b}}^{-1}$ of integrated luminosity in $p\bar{p}$ collisions collected by the CDF II detector at the Tevatron. A simultaneous measurement of the fractions of longitudinal ($f_0$) and right-handed ($f_{+}$) $W$ bosons yields the results $f_0=0.71_{-0.17}^{+0.18}(\mathrm{stat})\pm 0.06(\mathrm{syst})$ and $f_{+}=-0.07\pm 0.09(\mathrm{stat})\pm 0.03(\mathrm{syst})$. Combining this measurement with our previous result based on single lepton final states, we obtain $f_0=0.84\pm 0.09(\mathrm{stat})\pm 0.05(\mathrm{syst})$ and $f_{+}=-0.16\pm 0.05(\mathrm{stat})\pm 0.04(\mathrm{syst})$. The results are consistent with standard model expectation.

arXiv commentPublished in Phys. Lett. B

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Cited by in corpus (4)

• Model-independent measurement of the top quark polarisation
• Top Quark Physics at the Tevatron
• Measurements of the charge asymmetry in top-quark pair production in the dilepton final state at $\sqrt{s}=8$ TeV with the ATLAS detector
• Fully analytical O(α_s) results for on-shell and off-shell polarized W-boson decays into massive quark pairs