Model independent analysis of the forward-backward asymmetry of top quark production at the Tevatron

Motivated by a possible anomaly in the forward-backward (FB) asymmetry of top quark (AFB) observed at the Tevatron, we perform a model independent analysis on qq¯→tt¯ using an effective Lagrangian with dim-6 four-quark operators. We derive necessary conditions on new physics structures and the couplings that are consistent with the tt¯ production cross section and AFB measured at the Tevatron, and discuss possible new physics scenarios that could generate such dim-6 operators.