I will discuss the possibility of fingerprinting the presence of heavy
additional Z′ bosons that arise naturally in extensions of the
standard model , through their mixing with the standard model Z
boson. By considering a class of observables including total cross
sections, energy distributions and angular distributions of decay
leptons, a significant deviation from the standard model predictions
is observed for these quantities with right-handed electrons and
left-handed positrons at higher centre of mass energies. I will
further discuss how this process complements the study of fermion pair
production processes that have been considered for discrimination
between different models.