Top condensation as a motivated explanation of the top forward-backward asymmetry

TL;DR

This paper explores top condensation models, especially topcolor-assisted technicolor, as a natural explanation for the top forward-backward asymmetry, consistent with experimental data and offering testable LHC signatures.

Contribution

It demonstrates that top condensation models can explain the asymmetry through large top-up couplings and interference effects, aligning with experimental constraints.

Findings

Top condensation models can produce the observed top asymmetry.

Interference effects suppress the overall top pair production rate.

Models predict distinctive LHC signatures like top+jet resonances.

Abstract

Models of top condensation can provide both a compelling solution to the hierarchy problem as well as an explanation of why the top-quark mass is large. The spectrum of such models, in particular topcolor-assisted technicolor, includes top-pions, top-rhos and the top-Higgs, all of which can easily have large top-charm or top-up couplings. Large top-up couplings in particular would lead to a top forward-backward asymmetry through $t$-channel exchange, easily consistent with the Tevatron measurements. Intriguingly, there is destructive interference between the top-mesons and the standard model which conspire to make the overall top pair production rate consistent with the standard model. The rate for same-sign top production is also small due to destructive interference between the neutral top-pion and the top-Higgs. Flavor physics is under control because new physics is mostly confined to the top quark. In this way, top condensation can explain the asymmetry and be consistent with all experimental bounds. There are many additional signatures of topcolor with large tu mixing, such as top(s)+jet(s) events, in which a top and a jet reconstruct a resonance mass, which make these models easily testable at the LHC.