Measurement of the top quark forward-backward production asymmetry and its dependence on event kinematic properties

• Main Authors: Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Paus, Christoph M. E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2013-09-16T16:50:26Z.
• Subjects: Article
• Online Access: Get fulltext

 We present new measurements of the inclusive forward-backward tt̅ production asymmetry, A[subscript FB], and its dependence on several properties of the tt̅ system. The measurements are performed with the full Tevatron data set recorded with the CDF II detector during pp̅ collisions at √s=1.96  TeV, corresponding to an integrated luminosity of 9.4  fb[superscript -1]. We measure the asymmetry using the rapidity difference Δy=y[subscript t]-y[subscript t̅]. Parton-level results are derived, yielding an inclusive asymmetry of 0.164±0.047(stat+syst). We establish an approximately linear dependence of A[subscript FB] on the top-quark pair mass M[subscript tt̅] and the rapidity difference |Δy| at detector and parton levels. Assuming the standard model, the probabilities to observe the measured values or larger for the detector-level dependencies are 7.4×10[superscript -3] and 2.2×10[superscript -3] for M[subscript tt̅] and |Δy| respectively. Lastly, we study the dependence of the asymmetry on the transverse momentum of the tt̅ system at the detector level. These results are consistent with previous lower-precision measurements and provide additional quantification of the functional dependencies of the asymmetry.