Signature of Large Extra Dimensions from Z boson pair production at the CERN Large Hadron Collider

We study the Z boson pair production mediated by the Kaluza-Klein (KK) graviton in large extra dimensions (LED) at the CERN Large Hadron Collider (LHC). We use the partial wave unitarity to discuss the constraints on the process energy scale in order to give a self-consistent calculation. We find that the LED contributions can enhance the Z boson pair production cross sections significantly when the fundamental scale $M_S$ of the large extra dimensions is up to several TeV. We also show that the kinematic distributions of the LED signals are greatly different from the standard model ones and the LHC can probe the $M_S$ values up to $4.3\sim 5.6$ TeV at $3\sigma$ level depending on the number of the extra dimensions.