  In an $e^- p$ collider, a striking signature for a dilepton gauge boson is
\ep \ ; this cross-section is calculated by using the helicity amplitude
technique. At HERA, with center-of-mass energy $\sqrt s = 314 GeV$, a dilepton
mass above $150 GeV$ is inaccessible but at LEPII-LHC, with a center-of-mass
energy $\sqrt s = 1790 GeV $, masses up to 650 GeV can be discovered. In an
$e^+ e^-$ collider, the signature is \ee \ . The cross-sections of this process
are also calculated for the center-of-mass energies $\sqrt s = 200, 500$ and
$1000 GeV$.
