The Effects of a New Vector Boson on the Top Quark Cross Section at the   Tevatron
  It has recently been shown that a new neutral vector boson $Z'$, with a mass of order 1~TeV and weak couplings to quarks only, could explain both the anomalous values of $R_b$ and $R_c$ and the apparent excess of large $E_T$ jet events measured by the CDF collaboration. We calculate the effects of $Z'$ exchange on the $t\bar{t}$ production cross section at Tevatron $p \bar p$ collider energies, including next-to-leading-order QCD corrections. We find a significant enhancement of the cross section and study the resulting $t \bar t$ invariant mass distribution, which could provide a decisive test of the $Z'$ model. 
T.Gehrmann, W.J.Stirling