Bosons and Supersymmetry

A broad class of supersymmetric extensions of the standard model predict a Z 0 vector boson whose mass is naturally in the range 250 GeV<MZ0<2 TeV. To avoid unacceptably large mixing with the Z, one requires either a discrete tuning of the U(1)0 charges or a leptophobic Z 0. Both cases are likely to arise as the low energy limits of heterotic string compacti cations, but a survey of existing realistic string models provides no acceptable examples. A broken U(1)0 leads to additional D-term contributions to squark, slepton, and Higgs masses, which depend on the U(1)0 charge assignments and the Z 0 mass. The Tevatron and future colliders can discover or decisively rule out this class of models. To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics (Snowmass 96), Snowmass CO, June 25 July 12, 1996. Research supported by the U.S. Department of Energy under contract DEAC03-76SF00515.