We report the results of a search for a heavy neutral gauge boson Z'' decaying into the dielectron final state using data corresponding to an integrated luminosity of 5.4 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. No significant excess above the standard model prediction is observed in the dielectron invariant-mass spectrum.
We set 95 sigma(ppbar -} Z'') x BR(Z'' -} ee) depending on the dielectron invariant mass. These cross section limits are used to determine lower mass limits for bosons in a variety of models.
For the sequential standard model boson a lower mass limit of 1023 GeV is obtained.