Measurement of the Differential Cross Section d{\sigma}/d(cos {\theta}t) for Top-Quark Pair Production in p-pbar Collisions at sqrt{s} = 1.96 TeV

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We report a measurement of the differential cross section, d{\sigma}/d(cos {\theta}t), for top-quark-pair production as a function of the top-quark production angle in proton-antiproton collisions at sqrt{s} = 1.96 TeV.

• This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.4/fb.
• We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level.
• The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient, a1 = 0.40 +- 0.12, compared to the standard-model prediction of a1 = 0.15^{+0.07}_{-0.03}.