We measure the forward–backward asymmetry of the production of top-quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96\mathrm{TeV}$ using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of $9.1{\mathrm{fb}}^{-1}$. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks ($\mathrm{\Delta }y$) and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be $A_{\mathrm{FB}}^{t\overline{t}}=0.12\pm 0.13$, consistent with the expectations from the standard model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive $A_{\mathrm{FB}}^{t\overline{t}}$ in both final states yields $A_{\mathrm{FB}}^{t\overline{t}}=0.160\pm 0.045$, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of $\mathrm{\Delta }y$. A linear fit to $A_{\mathrm{FB}}^{t\overline{t}}(|\mathrm{\Delta }y|)$, assuming zero asymmetry at $\mathrm{\Delta }y=0$, yields a slope of $\alpha =0.14\pm 0.15$, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of $A_{\mathrm{FB}}^{t\overline{t}}(|\mathrm{\Delta }y|)$ in the two final states is $\alpha =0.227\pm 0.057$, which is $2.0\sigma$ larger than the SM prediction.

• Received 1 March 2016

DOI:https://doi.org/10.1103/PhysRevD.93.112005