feynrules-validator

name	feynrules-validator
description	Validate FeynRules .fr model files for physical consistency using Mathematica via Magnus cloud. Triggers when the user wants to check a .fr model file for Hermiticity, diagonal mass/quadratic terms, and kinetic term normalization.

FeynRules Validator

Overview

This skill validates FeynRules .fr model files for physical consistency by running four standard checks in both Feynman and Unitary gauge (8 checks total) using remote Mathematica execution via the Magnus cloud platform.

Validation is a critical step between writing a .fr model and generating a UFO model — it catches errors in the Lagrangian before they propagate to event generation.

Workflow

Step 1: Prepare the Model

Ensure the .fr file is complete and saved to disk. Know the exact Lagrangian symbol name (e.g., LSnew, Lag, LBSM).

Step 2: Run Validation

Execute the validate-feynrules blueprint using magnus run (see magnus skill):

magnus run validate-feynrules -- --model path/to/model.fr --lagrangian LSnew

Parameters:

Parameter	Required	Description
--model	Yes	Path to the .fr model file
--lagrangian	Yes	Exact Lagrangian variable name defined in the .fr file

The .fr file is automatically uploaded via the FileSecret mechanism.

Step 3: Interpret Results

The blueprint returns a JSON result (check with magnus job result <job-id>) containing:

• success (bool): True iff all 4 Unitary gauge checks pass. Feynman gauge results are informational only.
• verdict (str): Intelligent human-readable summary explaining the outcome — covers Goldstone mixing, field mixing, etc.
• feynman_gauge / unitary_gauge: Per-gauge results with 4 checks each:
  • hermiticity
  • diagonal_quadratic_terms
  • diagonal_mass_terms
  • kinetic_term_normalisation
• model_loading: Whether the model loaded successfully

Step 4: Fix and Re-validate

If validation fails:

1. Read the verdict field for guidance on what to fix
2. Edit the .fr file to correct the issues
3. Re-run validation

Model Type Auto-Detection

The validator auto-detects whether a model is:

• Standalone: Contains M$GaugeGroups — loaded directly
• BSM extension: No M$GaugeGroups — the built-in SM.fr is loaded first automatically

Success Criteria

• Success = True when all 4 Unitary gauge checks pass
• Feynman gauge failures are expected for models with spontaneous symmetry breaking (Goldstone boson artifacts)
• See references/validation_checks.md for detailed check descriptions and pass criteria

Reference Documentation

• See references/validation_checks.md for detailed explanation of each check, pass criteria, and gauge-specific behavior