We present a new measurement of the inclusive forward-backward tt¯ production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb−1 of pp¯ collisions at s√=1.96 TeV, recorded with the CDF-II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the tt¯ rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and t¯. In the tt¯ rest frame, the asymmetry is observed to increase with the tt¯ rapidity difference, Δy, and with the invariant mass Mtt¯ of the tt¯ system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large Δy and Mtt¯. For Mtt¯≥450 GeV/c2, the parton-level asymmetry in the tt¯ rest frame is Att¯=0.475±0.114 compared to a next-to-leading order QCD prediction of 0.088±0.013.
Evidence for a mass dependent forward-backward asymmetry in top quark pair production
Cauz D.;Santi L.;
2011-01-01
Abstract
We present a new measurement of the inclusive forward-backward tt¯ production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb−1 of pp¯ collisions at s√=1.96 TeV, recorded with the CDF-II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the tt¯ rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and t¯. In the tt¯ rest frame, the asymmetry is observed to increase with the tt¯ rapidity difference, Δy, and with the invariant mass Mtt¯ of the tt¯ system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large Δy and Mtt¯. For Mtt¯≥450 GeV/c2, the parton-level asymmetry in the tt¯ rest frame is Att¯=0.475±0.114 compared to a next-to-leading order QCD prediction of 0.088±0.013.File | Dimensione | Formato | |
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