Name: Francesco Date: 07/06/20-11:56:47 AM Z


Dear all,

I am new to FeynCalc and I want to use it to calculate NLO cross section for new Physics. I have my .fr rules which I used to generate UFO and FeynArts model files. Now I need to do something analytically.

In order to make the option paint work I had to use both my new .mod .gen and setting the option SetOptions[FourVector, FeynCalcInternal -> False];

In my model the SM is embedded so I was learning and testing it with some know process like qg->qg scattering at LO (https://feyncalc.github.io/FeynCalcExamplesMD/QCD/Tree/QGl-QGl).

I can draw the diagrams but when it comes to calculate the amplitude I get this error:

SharedObjects::failmsg: Error! FeynCalc has encountered a fatal problem and must abort the computation. The problem reads: SUNFIndex is not allowed inside SUNIndex

What am I missing? what do I have to change so that the contraction works?

Thanks a lot,
Francesco.