Revelations of the U(1)-Extended Supersymmetric Standard Model

If an extra supersymmetric U(1) gauge factor exists at the TeV energy scale, which is then broken together with the supersymmetry, there will be several interesting and important phenomenological consequences, not only at the TeV scale, but also at the 100 GeV scale. For one, the generic two-doublet Higgs structure will involve 3 additional parameters beyond that of the Minimal Supersymmetric Standard Model (MSSM), thereby raising the upper bound on the mass of the lighter of the two neutral Higgs scalars. For another, the supersymmetric scalar quarks and leptons receive new contributions to their masses from the spontaneous breaking of this extra U(1). Assuming a grand-unified E_6 gauge symmetry and universal soft supersymmetry-breaking terms at the grand-unification energy scale, we find solutions relating the U(1) breaking scale and the ratio of the vacuum expectation values of the two electroweak Higgs doublets.