== 4th Generation Model ==
=== Author ===
   * Claude Duhr 
      * IPPP Durham 
      * claude.duhr@durham.ac.uk 

=== Description of the model ===

This model is an extension of the SM, where a new fourth generation of fermions, a t' and a b' with SM couplings, is added. The CKM matrix is parametrized by Vtps and Vtpb, which are supposed small, and to leading order in the expansion in Vtps and Vtpb it is given by,

{{{
   1        0           0           0
   0   1-Vtps^2/2       0          Vtps
   0   -Vtps Vtpb   1-Vtpb^2/2     Vtpb
   0     -Vtps        -Vtpb       1-Vtps^2/2 -Vtpb^2/2
}}}

The particle content and the vertices of the model are summarized in the following [/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM.pdf pdf file].


=== Model files ===
   * [/attachment/wiki/FourthGeneration/4Gen.fr 4Gen.fr]: This is the main file. 
   * [/attachment/wiki/FourthGeneration/4Gen.nb 4Gen.nb]: This is an example Mathematica notebook that loads the model and calculates Feynman rules.  


== Matrix element generator files ==
Below we give tarballs containing the model files generated by !FeynRules for the various matrix element generaotrs for which a !FeynRules interface exists. All fermion masses are put to zero, except for the top, the bottom and the Tau lepton masses. Furthermore, in the CalcHep files, the CKM matrix is real.


||[/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM-CH.tgz 4th_Generation_Complex_CKM-CH.tgz]||The model files for !CalcHep.||
||[/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM_FA.tgz 4th_Generation_Complex_CKM_FA.tgz]||The model files for !FeynArts.||
||[/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM_MG.tgz 4th_Generation_Complex_CKM_MG.tgz]||The model files for !MadGraph 4.||
||[/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM_SH.tgz 4th_Generation_Complex_CKM_SH.tgz]||The model files for Sherpa.||
||[/attachment/wiki/FourthGeneration/4th_Generation_Complex_CKM_UFO.tgz 4th_Generation_Complex_CKM_UFO.tgz]||The model files in UFO format (e.g. for !MadGraph 5).||