J. Alwall, S. Hoeche, F. Krauss, N. Lavesson, L. Lonnblad, F. Maltoni,
M.L. Mangano, M. Moretti, C.G. Papadopoulos, F. Piccinini, S. Schumann,
M. Treccani, J. Winter, M. Worek
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 and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences.
LU TP 07-13, arXiv:0706.2569 [hep-ph]