== The Higgs effective theory ==
=== Author ===
   * Claude Duhr 
      * IPPP Durham
      * claude.duhr@durham.ac.uk 

=== Description of the model ===

This model describes the effective coupling of the Higgs boson to gluons and photons. The effective theory is obtained by integrating out the top-quark loop through which the higgs couples to gluons and photons. The corresponding effective theory for a pseudo-scalar is also included.

The values of the effective couplings correspond to those given in the heft model of the !MadGraph/MadEvent distribution.
=== References ===
   * " ''Gluon final states in higgs boson decay'' ", T.G. Rizzo, Phys. Rev., vol. D22, p. 178, 1980 
   * " ''Production of a higgs pseudoscalar plus two jets in hadronic collisions'' ", R.P. Kauffman and S.V. Desai, Phys. Rev., vol. D59, p.057504, 1999 
   * " ''Amplitudes for higgs bosons plus four partons'' ", R.P. Kauffman and S.V. Desai and D. Risal, 1999 

=== Model files ===
   * [http://europa.fyma.ucl.ac.be/~duhr/twiki/pub/Main/HiggsEffectiveTheory/HiggsEffective.fr HiggsEffective.fr] This is the main file. 
   * This model needs the model file of the [wiki:StandardModel SM implementation] of !FeynRules. 
=== <a name="Instructions"></a> Instructions ===

The model is loaded by merging the model files SM.fr and !HiggsEffective.fr (the two files must be stored in the same directory, see the [:UserManual:user manual]).

The implementation allows for the use of the Feynman gauge in the SM. Feynman gauge is '''not''' supported for this model.
=== <a name="Examples"></a> Examples ===
   * [http://europa.fyma.ucl.ac.be/~duhr/twiki/pub/Main/HiggsEffectiveTheory/HiggsEffective.nb HiggsEffective.nb] : This is an example Mathematica® notebook that loads the model and calculates Feynman rules. 
   * [http://europa.fyma.ucl.ac.be/~duhr/twiki/pub/Main/HiggsEffectiveTheory/HiggsEffective.tex HiggsEffective.tex] : This is TeX output written by !FeynRules.