Comparison of discovery limits forE6neutral gauge bosons at future colliders

We study and compare the phenomenology of extra ${\mathrm{E}}_6$ neutral gauge bosons at $e^{+}$ $e^{\mathrm{-}}$, ep, and hadron colliders. Our purpose is to compare the discovery reach of the various colliders and see how they compare in studying the phenomenology of extra neutral gauge bosons. We find that of the future colliders, hadron colliders probe the highest mass scales for the existence of extra neutral gauge bosons although precision measurements at $e^{+}$ $e^{\mathrm{-}}$ colliders, the SLAC Linear Collider & will put tight constraints on models predicting extra neutral gauge bosons. If deviations from the standard model are observed at ${\mathit{e}}^{+}$ ${\mathit{e}}^{\mathrm{-}}$ colliders at √As=${\mathrm{M}}_{\mathit{Z}}^0$, other measurements, especially those at the DESY ep collider HERA, will be necessary to unravel the physics. We also find that high-precision, low-energy neutral-current experiments will be competitive with $e^{+}$ $e^{\mathrm{-}}$ and ep colliders for detecting the presence of extra ${\mathrm{E}}_6$ neutral gauge bosons.