A Real Example: $H\rightarrow \gamma\gamma$ and $H\rightarrow Z \gamma$

I have made a detailed calculation of this process. An explanation of the calculation can be found in the file HiggsGammaGamma.pdf. Other relevant information can be obtained in the following files:

• The model file for QGRAF can be obtained gws-tHooftFeynmanGauge
• The QGRAF output file.
• You can also download a mathematica input file HGG.m for FeynCalc
• A related process that it is also needed to calculate the total Higgs boson width is the process $H\rightarrow Z \gamma$. You can also download a mathematica input file HGZ.m for this process.
• It is also available a fortran program hgg.F which uses the LoopTools package to evaluate the Passarino Veltman functions. The needed extra files can be found in the section Numerical Calculations.
• The final result for the various Branching Ratios is summarized in the following plot: