Generate UFO (Universal FeynRules Output) model directories from FeynRules .fr files via Magnus cloud. Triggers when the user has a validated .fr model and needs a UFO model for MadGraph5.
This skill generates UFO (Universal FeynRules Output) model directories from FeynRules .fr files using remote Mathematica execution via the Magnus cloud platform. UFO models are the standard interchange format between model-building tools (FeynRules) and Monte Carlo event generators (MadGraph5, Herwig, Sherpa).
Ensure the .fr file is validated (via feynrules-validator skill) and saved to disk. Know the Lagrangian symbol name (e.g., LSnew, LBSM).
Execute the generate-ufo blueprint using magnus run (see magnus skill):
magnus run generate-ufo -- --model path/to/model.fr --lagrangian LSnew --output path/to/MyModel_UFO
Parameters:
| Parameter | Required | Description |
|---|---|---|
--model | Yes | Path to the .fr model file |
--lagrangian | Yes | Lagrangian symbol from the .fr file |
--output | Yes | Output path for the generated UFO directory |
--restriction | No | Path to .rst restriction file |
The .fr file (and .rst if provided) is automatically uploaded via the FileSecret mechanism. On success, the UFO directory is automatically downloaded to --output.
WARNING: If --output points to an existing directory, it will be deleted and replaced by the download.
Model type is auto-detected:
M$GaugeGroups: loaded directly as standalone modelM$GaugeGroups: BSM extension — SM.fr and SM restrictions (Massless.rst, DiagonalCKM.rst) are loaded automaticallyAfter successful generation, you must read the UFO files to understand the model before using it with MadGraph5:
particles.py — particle definitions with MG5 names and PDG codes
name field: the particle name to use in MG5 generate commandspdg_code: needed for set param_card MASS <pdg> <value>parameters.py — parameter definitions with SLHA block info
lhablock + lhacode: needed for set param_card <block> <code> <value>value: default parameter valuesThis step is critical — particle names in MG5 come from the name field in particles.py, not from the ClassName in the .fr file.
Check the result JSON (magnus job result <job-id>):
success (bool): Whether generation succeededufo_path (str): Path to the downloaded UFO directoryIf warnings are present, review the UFO files carefully before proceeding to MadGraph5.
set param_card commands