Top quark forward-backward asymmetry from the 3-3-1 model

The forward-backward asymmetry A_FB in top quark pair production, measured at the Tevatron, is probably related to the contribution of new particles. The Tevatron result is more than a 2σ deviation from the standard model prediction and motivates the application of alternative models introducing new states. However, as the standard model predictions for the total cross section σ_tt and invariant mass distribution M_tt for this process are in good agreement with experiments, any alternative model must reproduce these predictions. These models can be placed into two categories: One introduces the s-channel exchange of new vector bosons with chiral couplings to the light quarks and to the top quark, and another relies on the t-channel exchange of particles with large flavor-violating couplings in the quark sector. In this work, we employ a model which introduces both s- and t-channel nonstandard contributions for the top quark pair production in proton-antiproton collisions. We use the minimal version of the SU(3)_C⊗SU(3)_L⊗U(1)_X model (3-3-1 model) that predicts the existence of a new neutral gauge boson, called Z^'. This gauge boson has both flavor-changing couplings to up and top quarks and chiral coupling to the light quarks and to the top quark. This very peculiar model coupling can correct the A_FB for top quark pair production for two ranges of Z^' mass while leading to a cross section and invariant mass distribution quite similar to the standard model ones. This result reinforces the role of the 3-3-1 model for any new physics effect.