Model identification of new heavy Z′ bosons at ILC with polarized beams

Extra neutral gauge bosons, Z's, are predicted by many theoretical scenarios of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible that Z's are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z' exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the expected sensitivity to Z' parameters of fermion-pair production cross sections at the planned International Linear Collider (ILC), especially as regards the potential of distinguishing different Z' models once such deviations are observed. Specifically, we evaluate the discovery and identification reaches on Z' gauge bosons pertinent to the E-6, LR, ALR, and SSM classes of models at the ILC.