Changes between Version 9 and Version 10 of FormFactors


Ignore:
Timestamp:
12/12/13 11:45:04 (6 years ago)
Author:
omatt
Comment:

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  • FormFactors

    v9 v10  
    1 === How to add momentum dependent form factors? in UFO model===
    2 
    3 === Compatible model.
     1[[PageOutline(1,Page Contents,inline)]]
     2
     3= Method 1: Pure Python (UFO/ALOHA) =
     4
     5== Compatible model. ==
    46
    57All UFO model are not ready to use form-factor (all recent one should be).
     
    1517}}}
    1618
    17 === Defining your form factor:
     19== Defining your form factor: ==
    1820
    1921create/edit the file form_factors.py
     
    3739
    3840
    39 === Add the vertex dependencies in your form factor:
     41== Add the vertex dependencies in your form factor: ==
    4042
    4143Go in the file vertices.py and identify the interactions that you want to modify:
     
    8486
    8587
    86 === For More complex formfactor (Those who cann't be written in one line).
     88= Method 2: Fortran Way =
     89This method is intended for More complex formfactor (Those who cann't be written in one line).
    8790
    8891If the formfactor is a very complex function with a lot of "if" statement (like those obtained if when you add a form-factor to have the vertex associated to a full loop).
     
    115118}}}
    116119
    117 === How to add momentum dependent form factors? in v4 model===
     120= Method 3: Expert Mode =
     121
     122You can fully bypass ALOHA by setting the lorentz structure to external
     123{{{
     124VVS2 = Lorentz(name = 'VVS2',
     125               spins = [ 3, 3, 1 ],
     126               structure = 'external') 
     127}}}
     128You are then '''responsible''' to provide the functions yourself.
     129Each routines (VVS2_0.f, VVS2_1.f, ..., VVS2_0.py, ...) need to be set in the directory UFO_DIR/Fortran, UFO_DIR/Python, UFO_DIR/CPP
     130
     131A typical way to use this mode is first to ask MG5 to create those files (via the mg5 command output aloha VVS2_0 --format=Fortran).
     132Then set the structure on external and modify manually the file created by ALOHA.
     133
     134
     135
     136= V4 MODEL (OLD model format)=
     137
    118138The easiest way to implement momentum dependent form factors, without changing all the details in the
    119139{{{
     
    214234in the model directory so that you won't forget for which process you created this model.)
    215235
    216 -- Main.RikkertFrederix - 20 Jul 2008
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