  A spin-3/2 top quark excitation originating in string realisations of the RS
scenario has an effect on the production of top-antitop pairs in hadron-hadron
collisions. We study the additional contribution of this state to the cross
section for the LHC. We comment on the prospect of discovery or exclusion for a
range of masses and couplings at both 7 and 14 TeV and show that the reach
extends significantly with increasing centre-of-mass energy. Results are
compared with the effect of a hypothetical spin-1/2 excited top as well as
other BSM scenarios which predict the presence of higher dimension effective
operators. We also calculate distributions for several observables which can be
used to distinguish between the different scenarios in the presence of a
deviation from the SM prediction for the ttbar cross section.
