Influence of Graviton on Top-antitop Production at the LHC
We examine the top quark production in the brane world scenario. We study two typical models - the model proposed by Arkani-Hamed, Dimopoulos and Dvali (ADD) and the model of Randall and Sundrum (RS). In addition to the Standard Model processes, there is a new contribution to the top-antitop pair production process mediated by graviton Kaluza-Klein modes in the s-channel. We calculated the density matrix for the top-antitop pair production including the new contribution. With a reasonable parameter choice, we find a sizable deviation of the top-antitop quark spin correlations from those in the Standard Model.