Name: Vladyslav Shtabovenko Date: 11/04/15-11:47:53 AM Z


Hi,

sorry for the late reply, at the moment I’m working on a larger update
to FeynCalc with some nice features.

In general, OneLoop is a sort of legacy function with a lot of code that
is used only there and nowhere else. It seems that it is not able to do
the tensor decomposition correctly, if OneLoop is not allowed to cancel
scalar products beforehand (CancelQP->True).

To avoid this issue, I will remove the CancelQP option. I also recommend
you to use TID instead:

TID[SP[q1, q1] FAD[{q1, m1}, {q1 + kk1, m2}, {q1 + kk2, m3}], q1]

Cheers,
Vladyslav

Am 02.11.2015 um 19:06 schrieb Xing:
> Hi,
> When I tried to do OneLoop with CancelQP set to be False as below,
>
> OneLoop[q1, SP[q1, q1] FAD[{q1, m1}, {q1 + kk1, m2}, {q1 + kk2, m3}],
> CancelQP -> False]
>
> the result gave me a constant term, -i*Pi/2, besides the tensor coefficients.
> Why does this happen? I tried both FC8 and FC9.
>
> Best,
> Xing
>