Forward-backward asymmetry of top quark in diquark models

Abstract

Motivated by the recent unexpected large forward-backward asymmetry (FBA) of the top quark observed by D$\text{O}$ and CDF at the Tevatron, we investigate a possible explanation for the anomaly within the framework of diquark models. Unlike other mechanisms induced by s-channel or t-channel, the top-quark pair production in the diquark models is dictated by the u-channel diagram. We find that the color-triplet diquark can generate the FBA of 20% when the constraint from the cross section of the top-quark pair production is taken into account.

Comments: 12 pages, 5 figures. Discussion and figures improved. Version accepted for publication in PRD