Uses and abuses of effective Lagrangians

Motivated by past and recent analyses we critically reexamine the use of effective Lagrangians in the literature to constrain new physics and to determine the "physics reach" of future experiments. We demonstrate that many calculations, such as those involving anomalous trilinear gauge-boson couplings, either considerably overestimate loop-induced effects or give ambiguous answers. The source of these problems is the use of cutoffs to evaluate …