MadGraph Interface

A small library of matrix elements obtained with MADGRAPH version 4 (MG4) are included with the standard VINCIA release. (In the future, matrix elements for additional processes will be available for download from the VINCIA homepage.) Through its MG interface, VINCIA is able to match to these matrix elements during the shower evolution.

flag  Vincia:MGInterface   (default = on)
The MGInterface must be switched on for matching to work properly.

Note: see the section on Useful References for additional references to include when using the matrix elements provided by this interface.

Note 2: parts of the MADGRAPH code (specifically the HELAS libraries) are needed at runtime to evaluate the MADGRAPH matrix elements. The Makefile distributed with VINCIA will automatically attempt to download and install the MADGRAPH standalone tarball for you, if it doesn't find it in the expected location, and will then compile the relevant libraries from it. If this fails, we recommend having a look in the Makefile before contacting the authors. Large parts of the Makefile have been made user-editable in hopefully straightforward ways, and it may be possible for you to solve the problem by trivial editing.

Importing new matrix elements from MadGraph

The procedure for including a new matrix element is not intended for general users at this point, but is documented here for reference:

The MADGRAPH matrix elements included with VINCIA are located together with the actual interface code in VINCIA's MGInterface/ subdirectory. They are ordinary MADGRAPH matrix element routines, which have been renamed and modified slightly for use by VINCIA. Most of this conversion is done automatically, by a script. Implementing new matrix elements should therefore be fairly trivial, as long as the final state corresponds to something that VINCIA can actually generate. (E.g., implementing matrix elements for DIS or hadron-collider processes will not suddenly make VINCIA able to handle such cases, since the shower is not yet developed for that.)

Procedure: