Changes between Version 4 and Version 5 of HelpSyntax

Timestamp:

Jul 26, 2010, 3:23:46 PM (15 years ago)

Author:

Johan Alwall

Comment:

--

HelpSyntax

@@ -1 @@
-== !MadGraph5 Syntax For generate events ==
+== !MadGraph5 Syntax for process generation ==
 
-Compared to [http://madgraph.phys.ucl.ac.be/EXAMPLES/example.html MG4 the syntax] is basically the same
-but 
+Most of the [http://madgraph.phys.ucl.ac.be/EXAMPLES/example.html MG4 syntax] is kept unchanged, but in MG5,
    1. All particles should be separated with a spaces
 {{{
@@ -10 +9 @@
    w+>vee+
 }}}
-   2. The coupling is specify after the process in the same line. 
+   2. The coupling order is specified after the process, on the same line. 
       Please note that:
-        a. Note that contrary to !MG4 the default for the coupling is to infinity
+        a. Note that contrary to MG4 the default coupling order is infinity
         b. couplings are case sensitive
 {{{
 write this:
-   w+ > ve e+ QED=2
+   p p > ve e+ j j QED=2
 and not:
-   w+>ve e+ qed=2
+   p p > ve e+ j j qed=2 qcd=99
 }}}
-   3. you can still use the special tag at the end of the process
-      a. "/" fordids the following particles to appear in the process
-      b. "$"  fordids the following particles to appear in a S-Channel
+   3. Other special process definition tags are the same:
+      a. "p p > w+ > j j j" allows only diagrams with a W+ as an s-channel propagator
+      b. "e+ e- > e+ e- / z" forbids Z to appear in any internal line in the process
+      c. "p p > ul ul~ j $ go"  forbids go to appear in any s-channel propagator
 
-   4. The syntax for decay chain is different.
-      a. In !MG5 the production process is separated from the decay by a coma. 
-      b. Each part can be restricted by couplings/ special tag restrictions
+   4. *The syntax for decay chain is different.*
+      a. In MG5 the production process is separated from the decays by a comma. 
+      b. Each subprocess (core process or decay) can have coupling orders/special tag restrictions
 {{{
 write this:
-   g g > t t~ QED=0 /a, (t > b W+, W+ > l+ vl), t~ >j j j QCD=0
+   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)      
+   g g > (t > b (W+ > l+vl))(t~ > j j j)      
 }}}
-   Note that If you run MG5 on MG4 proc_card. for a decay chains, then the couplings restriction will be applied only on the core process.
+   Note that if you run MG5 using an MG4 proc_card, then the coupling orders will act as in MG4.