Working Group 1 / Working Group 2 / Working Group 3 / Working Group 4

Working Group 2 - Interface development

• I. Python interface.
  • Description: development of a FeynRules Python interface, which will be used by MG and Herwig
  • Names: Claude, David, Olivier, Will.
  • Status:
    • We decided that a model is a Python package, where particles, parameters, etc. are represented as objects. The package will be self-contained in the sense that it provides everything required for the module (definition of the classes, etc.)
    • For the moment particles and parameters are written automatically from FR.
    • We created a "dummy model", based on the Fr implementation of the Hidden Abelian Higgs model of FR, where we added a vertex u,u,Z' by hand.
  • To-do:
    • Some tuning for the parameters needs to be done, especially "Waterfall structure".
    • Some python files need to be added to the package, e.g. , functions like sqrt, sin, etc.
    • We have now the option to matrices as matrices, rather than component by component. This needs to be discussed and developped further.
    • The parts dealing with the vertices, couplings, etc. need to be written. Will is working on splitting the FR vertices into triplets according to color, lorentz_structure and coupling. After this is done, Claude will create the writing routines for vertices.
    • David is developing the Herwig part of the Python interface.

• II. Helas.
  • Description: automatized generation of Helas routines from FeynRules, both in Fortran for MG and in C++ for Herwig.
  • Names: Olivier, Claude, Will, Priscila, David
  • Status:
    • We have a defined format for the FR output (via a class)
    • We have produce our first generated automaticaly Helas Routine from FeynRules.
    • Testing those routines is in progress
  • To-do:
    • Python Optimization (code quite slow at the time)
    • Regenerate all the Helas routine and test those against the old one
    • Implement the Scalar in the FortranWriter
    • Implement Helas Optimization
    • Implement a mode for complex couplings/masses

• III. FeynArts interface.
  • Description: inclusion of the higher dimensional operators in FeynArts.
  • Names: Celine, Thomas
  • Status:
    • Format of the FR output for the dirac indices is defined (Implementation in FR in progress).
    • addition of the dirac indices in FeynArts/FormCalc in progress.
    • Test in progress : EQCD done (FA only), composite top (FR files used in FA), BFSM (comparison with stock version started).
  • To-do:
    • Define format for the levi-civita tensor and implement it.
    • generate declaration file for FormCalc.
    • Merging of the vertices in FR.
    • Test SILH + renormalizable theories.