Probing the Tevatron t(t)over-bar asymmetry at LHC

We use an effective operator framework to study the contributions to the Tevatron t (t) over bar asymmetry from arbitrary vector bosons and scalars, and compare with their effect on the t (t) over bar tail at LHC. Our study shows, for example, that models reproducing the t (t) over bar asymmetry by exchange of Z' and W' bosons or colour-triplet scalars lead to a large enhancement in the t (t) over bar tail at LHC. This fact can be used to exclude these models as the sole explanation for the asymmetry, using the data already collected by CMS and ATLAS. Our analysis is model independent in the sense that we scan over all possible extra particles contributing to the asymmetry, and allow for general couplings. We also explore a class of Standard Model extensions which can accommodate the Tevatron asymmetry without contributing to the total t (t) over bar cross section at first order, so that the enhancement of the tail at Tevatron and LHC is moderate.