Matching Parton Showers and Matrix Elements
  We compare different procedures for combining fixed-order tree-level matrix element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW scheme and one based on the so-called MLM scheme using different matrix element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences. 
Stefan Hoeche, Frank Krauss, Nils Lavesson, Leif Lonnblad,   Michelangelo Mangano, Andreas Schaelicke, Steffen Schumann