Dilepton gauge bosons: Present status and future prospects

Dilepton gauge bosons which appear in a class of unified models are studied both from the point of view of existing data and of future experiments. Present data allow masses only above 120 GeV. Future experiments in $e^{+}{e}^{-}$ scattering can improve this bound to 600 GeV (CERN $e^{+}{e}^{-}$ collider LEP II with $\sqrt{s}=200\mathrm{}$ GeV) and to 1500 GeV (Next Linear Collider $e^{+}{e}^{-}$ with $\sqrt{s}=500\mathrm{}$ GeV). The process $e^{+}{e}^{-}\to {\mu }^{-}{\mu }^{-}$ could provide an excellent signature for the existence of dilepton gauge bosons in an $e^{-}{e}^{-}$ collider, even for $\sqrt{s}=100\mathrm{}$ GeV.