The Top Quark Production Asymmetries $A_{FB}^t$ and $A_{FB}^{\ell}$
  A large forward-backward asymmetry is seen in both the top quark rapidity distribution $A_{FB}^t$ and in the rapidity distribution of charged leptons $A_{FB}^\ell$ from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data. 
Edmond L. Berger, Qing-Hong Cao, Chuan-Ren Chen, Jiang-Hao Yu, Hao   Zhang
hep-ph hep-ex