An Electroweak Weizsacker-Williams Method
  The Weizsacker-Williams method is a semiclassical approximation scheme used to analyze a wide variety of electromagnetic interactions. It can greatly simplify calculations that would otherwise be impractical or impossible to carry out using the standard route of the Feynman rules. With a few reasonable assumptions, the scope of the method was generalized so as to accommodate weak, as well as the usual electromagnetic, interactions. The results are shown to be in excellent agreement, in the high energy limit of interest, with other methods, and the generalized scheme is shown to still work in regimes of analysis where those methods break down. 
Sean C. Ahern