Name: Ismail Turan (email_not_shown)
Date: 09/27/05-10:43:55 AM Z

Hi Rolf,

I guess you recieved my email with the notebook file. As you said you are busy and probably didn't find time to check.

I just wanted to update you what I did after that. Obviously I got more experience with FeynCalc by playing with FeynCalc even though I was supposed to finish a messy calculation:)
In addition to the simplifications I did to the matrix elements before using OneLoop, I also am using mathematica in batch mode and this helped as well to do the calculation faster but still not the best.

However, while I was looking the output from, after OneLoop routine, one of the matrix element in the notebook(that I called WSelfonglnC1), I realized that there are vectors having a dummy index called $mud[2], more specificially of the form FV[Polarization[k2, I],
     HighEnergyPhysics`fctools`OneLoop`Private`mud[2]]. Of course nothing is wrong with that as long as the whole term is scalar which must be the case since I also included two polarization vectors for the final state gluons. But, Such terms has factors carrying NO such free index $mud[2]!!

This cannot be the case since we started from a Lorentz scalar matrix element and ended up after loop integration with some terms having a free index $mud[2] which is supposed to be dummy by definition. I am pretty sure that OneLoop does some wrong things especially at the stage extracting loop momentum dependent terms from scalar products.

The solution that I found to this is NOT to include two polarization vectors of the gluons at the first place and leave the matrix a second rank tensor and see what I am getting from the loop integration. Interestingly enough, this time I am getting something which at least has NO such obviously problematic terms.

So, there might be a problem for OneLoop in handling the polarization vectors when they are contracted with especially the momentum over which the loop integration is going to be carried out.

Sorry about such a long email.

Thank a lot for your time,
Best Regards,


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