Influence of Z' boson on top quark spin correlations at the LHC
  We study top-antitop pair production and top spin correlations in a model with an electrically neutral massive gauge boson, Z', at the Large Hadron Collider. In addition to the Standard Model processes, the Z' contributes to the top-antitop pair production process in the s-channel. Choosing a kinematical region of top invariant mass around the Z' resonance pole, we find sizable deviations of the top-antitop pair production cross section and the top spin correlations from those of the Standard Model. 
Masato Arai, Nobuchika Okada, Karel Smolek, Vladislav Simak