Low-energy constraints on new physics reexamined

It is possible to place constraints on non-standard-model gauge-boson self-couplings and other new physics by studying their one-loop contributions to precisely measured observables. We extend previous analyses which constrain such nonstandard couplings, and we present the results in a compact and transparent form. Particular attention is given to comparing results for the light-Higgs scenario, where nonstandard effects are parametrized by an effective Lagrangian with a linear realization of the electroweak symmetry-breaking sector, and the heavy-Higgs or strongly interacting scenario, described by the electroweak chiral Lagrangian. The constraints on nonstandard gauge-boson self-couplings which are obtained from a global analysis of low-energy data and CERN LEP or SLC measurements on the $Z$ pole are updated and improved from previous studies.