ar X iv : h ep - p h / 04 08 09 8 v 1 6 A ug 2 00 4 Z ′ Gauge Bosons at the Tevatron

We study the discovery potential of the Tevatron for a Z ′ gauge boson. We introduce a parametrization of the Z ′ signal which provides a convenient bridge between collider searches and specific Z ′ models. The cross section for pp → Z X → l+l−X depends primarily on the Z ′ mass and the Z ′ decay branching fraction into leptons times the average square coupling to up and down quarks. If the quark and lepton masses are generated as in the standard model, then the Z ′ bosons accessible at the Tevatron must couple to fermions proportionally to a linear combination of baryon and lepton numbers in order to avoid the limits on Z − Z ′ mixing. More generally, we present several families of U(1) extensions of the standard model that include as special cases many of the Z ′ models discussed in the literature. Typically, the CDF and D0 experiments are expected to probe Z -fermion couplings down to 0.1 for Z ′ masses in the 500–800 GeV range, which in various models would substantially improve the limits set by the LEP experiments.