We present a new measurement of the inclusive forward-backward
tt-bar production asymmetry and its rapi+dity and mass dependence.
The measurements are performed with data corresponding to an integrated
luminosity of 5.3 fb-1 of p anti-p collisions at s**(1/2) ñ.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-bar rest frame, and in both cases are found to be consistent
with CP conservation under interchange of t and t-bar. In the tt-bar
rest frame, the asymmetry is observed to increase with the tt-bar
rapi+dity difference, Delta y, and with the invariant mass M_tt-bar of
the tt-bar 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 Delta y and M_tt-bar. For M_tt-bar > 450 GeV/c2,
the parton-level asymmetry in the tt-bar rest frame is Att-bar ð.475
+/- 0.114 compared to a next-to-leading order QCD prediction of 0.088
+/- 0.013.
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Updated: Wednesday, 2011 June 08 14:53:50 CDT automatically from input from "Carol Picciolo"