The axigluon, a four-site model and the top quark forward-backward asymmetry at the Tevatron

Very recently, it has been shown by other authors that the CDF measurement of the top quark forward-backward asymmetry can be explained by means of a heavy and broad axigluon. In order to work, this mechanism needs that the axigluon coupling to the top quark must be different than the coupling to light quarks and both must be stronger than the one predicted in classical axigluon models. In this Letter, we argue that this kind of axigluon can be accommodated in an extended chiral color model we proposed previously. Additionally, we show that the desired features can be derived from a simple four-site model with delocalized fermions.