Precision electroweak experiments and heavy physics: A global analysis

The radiative corrections of heavy degenerate and nondegenerate electroweak multiplets do not decouple from low-energy experiments. Their effects can be parametrized in a general renormalization-scheme-independent way. For isospin-breaking h_V and chiral-breaking h_AZ and h_AW, derived from the Z and W self-energies, a global analysis of existing neutral-current and Z and W data yields -1.2<h_V<0.9, -3.5<h_AZ<1.0, -4.4<h_AW<2.4 (90% C.L.). The expectations for future experiments are described, and the implications for the top-quark and Higgs-boson masses, new generations, supersymmetry, and technicolor are discussed.