Version 6 (modified by JohanAlwall, 10 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)      

Note that if you run MG5 using an MG4 proc_card, then the coupling orders will act as in MG4.