QGRAF

This program generates Feynman diagrams for any process. It was done by Paulo Nogueira working at CeFEMA. Different models can be studied. There is no graphics output. The program can be downloaded from QGRAF Home Page. The manual comes with the package.

To compile you need a Fortran compiler. In Linux the command line is

gfortran qgraf-3.x.y.f -o qgraf

where x and y are the last version numbers and qgraf is the executable file. In Windows see explanation at the end.

It gives the correct symmetry factors among diagrams. For example for the Bhabha Scattering ( $e^- e^+ \rightarrow e^- e^+$) an input file will look like this. You can look at the QED Model file and at the corresponding output file.

For the Standard Model the following information is relevant:

• The model file for QGRAF in the 't Hooft-Feynman gauge (for one–loop calculations), can be obtained SM-Rxi-CKM-Id

• The model file for QGRAF in the Unitary Gauge (for tree level calculations), can be obtained SM-UnitaryGauge-CKM-Id. Notice that the couplings with an * at the beginning are commented. If you want to include the Higgs couplings to light fermions and/or a CKM not equal to unity you should uncomment those entries.

• Examples of models for qgraf can be found here.