We present results of searches for technirho (ρT), techniomega (ωT), and Z′ particles, using the decay channels ρT,ωT,Z′→e+e−. The search is based on 124.8pb−1 of data collected by the D0 detector at the Fermilab Tevatron during 1992–1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp¯→ρT,ωT,Z′→e+e− as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate ρT and ωT states with masses below about 200 GeV. We exclude a Z′ with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.Received 24 February 2001DOI:https://doi.org/10.1103/PhysRevLett.87.061802©2001 American Physical Society