Shaping the top asymmetry

We study different profiles of the distribution of the top forward-backward asymmetry, as a function of the invariant mass of the t (t) over bar pair. We show that they can be reproduced by one or more light colour octets, while keeping moderate departures of the t (t) over bar cross section and invariant mass distributions with respect to the Standard Model predictions at Tevatron and LHC. (C) 2011 Elsevier B.V. All rights reserved.