Axigluons cannot explain the observed top quark forward-backward asymmetry

Abstract

We study an SU(3)^2 axigluon model introduced by Frampton, Shu, and Wang to explain the recent Fermilab Tevatron observation of a significant positive enhancement in the top quark forward-backward asymmetry relative to standard model predictions. First, we demonstrate that data on neutral B_d-meson mixing excludes the region of model parameter space where the top asymmetry is predicted to be the largest. Keeping the gauge couplings below the critical value that would lead to fermion condensation imposes further limits at large axigluon mass, while precision electroweak constraints on the model are relatively mild. Furthermore, by considering an extension to an SU(3)^3 color group, we demonstrate that embedding the model in an extra-dimensional framework can only dilute the axigluon effect on the forward-backward asymmetry. We conclude that axigluon models are unlikely to be the source of the observed top quark asymmetry.

12 pages, 7 eps figures included. Minor changes to conform with published version

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Cited by in corpus (8)

• Probing the Tevatron t tbar asymmetry at LHC
• Top Quark Forward-Backward Asymmetry and Same-Sign Top Quark Pairs
• Top quark forward-backward asymmetry at Tevatron and its implications at the LHC
• New Strongly Coupled Sector at the Tevatron and the LHC
• Gluon excitations in t tbar production at hadron colliders
• One-side forward-backward asymmetry at the LHC
• Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production
• QCD correction to single top quark production at the ILC