FeynWrite

Automate the production of FeynRules files.

Currently the library defines a simple domain-specific language related to writing down terms in the Lagrangian, which are then exported to the FeynRules format. This provides a number of advantages:

• Reduces boilerplate code often present in FeynRules model files
• Allows various checks to be done that guarantee the validity of the exported file
• Defines an extensible and (arguably) simpler input for the terms
• Allows the .symm and .gauge files required by matchmakereft to be produced automatically for a given model
• Facilitates exporting to another format (e.g. Matchete, LaTeX)
• Sets the stage for automating the definition of these terms

Installation

If you don't use pipx, you're missing out. Here are installation instructions

Simply run:

$ pipx install .

Lagrangian

Modifications to the common Lagrangian can be made in the granada.py file. Important notes:

• Spinors with contracted indices should be written next to each other
• Adjoint SU(2) indices should be written in the opposite position to where they are if they are conjugated, since the conjugation function swaps the index position
• Be a bit careful taking the charge conjugate .CC of chiral fermions; better to project out the component of the other fermion in the current

Usage

To use it:

$ feynwrite [MULTIPLET]...

For help:

$ feynwrite --help