Name: Vladyslav Shtabovenko Date: 06/29/15-11:39:06 AM Z


Hi Anne,

thanks for you mail. There is indeed an issue that ToTFI
is unable to do to the conversion because of q1+p (TARCER expects q1-p).
I’ll fix it. For now you can just flip the sign of q1 by hand (which is
fine since it is a loop variable)

Contract[fAmp // ChangeDimension[#, D] \&] // DiracSimplify //
 SPC[#, q1, q2] &`//ReplaceAll[#,q1->-q2]// ToTFI[#, q1, q2, p] &

I added ChangeDimension here, since the output of FeynArts is 4D.
DiracSimplify and SPC are needed to simplify the Dirac algebra and
cancel scalar products in the denominator.

As a cross-check for TARCER I would recommend using Smirnov’s FIRE
(https://bitbucket.org/feynmanIntegrals/fire)

Cheers,
Vladyslav

Am 29.06.2015 um 07:59 schrieb Anne Ernst:
> Hello,
>
> I would like to use FeynArts, FeynCalc and Tarcer in order to calculate
> 2-loop self-energy type integrals.
> In order to do so, I am translating my FeynArts-output to FeynCalc and then
> apply the function ToTFI. However it doen’t seem to work, I don’t get any
> TFI’s in the resulting expression…
> (I have also tried contracting my amplitude first.)
>
>
> Mathematica9.0, FeynCalc9.0
>