How do I implement my own cuts in MadEvent ?

From the web, cuts can be only set among those provided in the run_card.dat.

To add new cuts, one needs

1. to know a bit of fortran
2. to download the code (either after process generation or from our Download page) and run on your local machine.

If you just want to hard-code a cut, all you need to do is modify the file SubProcesses/cuts.f, where all external particle 4-momenta are given in the P(0:3,nexternal) array (energy in P(0,I) and 3-momenta in P(1:3,I)). The order of the external particles depends on the subprocess, and can be guessed from the name of the subprocess Pxxxxxxx directory or can be seen from the Pxxxxxxx/leshouche.inc file.

If you want to "standardize" your cuts and be able to change them from the run_card.dat as the default madgraph cuts, you need to modify the files

• Source/setrun.f (which reads the run_card.dat)
• SubProcesses/cuts.inc
• SubProcesses/cuts.f

which appear in Template or in the process dependent code that you downloaded from the web (madevent.tar.gz). You can use e.g. the cut xptj as a template for your new cut.

-- Main.JohanAlwall - 2011-10-19