Several reasonably model-independent formulations of the implications of new physics for precision electroweak measurements have been developed over the past years, most notably by Peskin and Takeuchi, and by Altarelliet al. These formulations work by identifying a small, but useful, set of parameters through which new physics often enters into well-measured physical observables. For the theories to which such an analysis applies, this approach greatly streamlines the confrontation with the data. Since the experimentally-allowed range for these parameters has been determined from global fits to the data, theorists need only compute their predictions for these parameters to constrain their models. We summarize these methods here, together with several recent generalizations which permit applications to wider classes of new physics, and which include the original approaches as special cases.

The inflationary paradigm provides a robust description of the peculiar initial conditions which are required for the success of the hot Big Bang model of cosmology, as well as of the recent precision measurements of temperature fluctuations within the cosmic microwave background. Furthermore, the success of this description indicates that inflation is likely to be associated with physics at energies considerably higher than the weak scale, for which string theory is arguably our most promising candidate. These observations strongly motivate a detailed search for inflation within string theory, although it has (so far) proven to be a hunt for a fairly elusive quarry. This article summarizes some of the recent efforts along these lines, and draws some speculative conclusions as to what the difficulty in finding inflation might mean.