Left-right asymmetries and exotic vector-boson discovery in   lepton-lepton colliders
  By considering left-right (L-R) asymmetries we study the capabilities of lepton colliders in searching for new exotic vector bosons. Specifically we study the effect of a doubly charged bilepton boson and an extra neutral vector boson appearing in a 3-3-1 model on the L-R asymmetries for the processes $e^-e^-\to e^-e^-$, $\mu^-\mu^-\to\mu^-\mu^-$ and $e^-\mu^-\to e^-\mu^-$ and show that these asymmetries are very sensitive to these new contributions and that they are in fact powerful tools for discovery this sort of vector bosons. 
J. C. Montero, V. Pleitez and M. C. Rodriguez