Top-quark forward-backward asymmetry from a color-octet t-channel resonance

Abstract

We consider new physics contributions to the top-quark forward-backward asymmetry from a neutral V-8(0) or charged V-8(+) color-octet vector exchanged in the t channel. We study the phenomenological constraints on these particles arising from the Tevatron and LHC7 measurements and compare them with those on their color-singlet counterparts Z' and W'. We find that the color octets fare better than the singlets in that they generate a lower A(C), a lower high-invariant mass cross section at LHC7 and a lower same sign top-pair cross section. However, they also generate a lower A(FB) than their color-singlet counterparts.