Version 8 (modified by trac, 6 years ago) (diff)


!MadGraph5 Syntax for process generation

In MadGraph 5, most of the MG4 syntax is kept unchanged, but in MG5,

  1. All particles should be separated with a spaces
    write this:
       w+ > ve e+
    and not:
  2. The coupling order is specified after the process, on the same line. Please note that:
    1. Note that contrary to MG4 the default coupling order is infinity
    2. couplings are case sensitive
      write this:
         p p > ve e+ j j QED=2
      and not:
         p p > ve e+ j j qed=2 qcd=99
  3. Other special process definition tags are the same:
    1. "p p > w+ > j j j" allows only diagrams with a W+ as an s-channel propagator
    2. "e+ e- > e+ e- / z" forbids Z to appear in any internal line in the process
    3. "p p > ul ul~ j $ go" forbids go to appear in any s-channel propagator
  1. The syntax for decay chain is different.
    1. In MG5 the production process is separated from the decays by a comma.
    2. Each subprocess (core process or decay) can have coupling orders/special tag restrictions
      write this:
         g g > t t~ / a QED=0, (t > b W+, W+ > l+ vl), t~ >j j j QCD=0
      and not:
         g g > (t > b (W+ > l+vl))(t~ > j j j)