Name: Vladyslav Shtabovenko Date: 08/03/14-10:01:55 PM Z
Hi,
if I enter
Tr1a =
Tr[GS[P1].GS[P2].GS[P3].GA[i].(1 -
GA[5])];
Tr2a =
Tr[GS[Q1].GS[Q2].GS[Q3].GA[i].(1 -
GA[5])];
Tr3a = Tr[
GS[P1].GS[P2].GS[P3].GA[i].GS[Q1].GS[Q2].GS[Q3].GA[i].(1
then
Result = Simplify[Contract[Tr1a.Tr2a + 2 Tr3a]] // Schouten
indeed returns zero.
Cheers,
Vladyslav
Am 03.08.2014 20:38, schrieb Nikita Belyaev:
> Good day,
> I’ve tried to calculate some matrix elements and I’ve faced with a
bug.
> As an example I can provide the following calculation.
> Here are the well-known formula to calculate some trace combinations
(FeynCalc syntaxis):
>
> Tr1a = Tr[P1.P2.P3.GA[i].(1 - GA[5])];
> Tr2a = Tr[Q1.Q2.Q3.GA[i].(1 - GA[5])];
> Tr3a = Tr[P1.P2.P3.GA[i].Q1.Q2.Q3.GA[i].(1 -
GA[5])];
>
> Result = FullSimplify[Contract[Tr1a.Tr2a + 2
Tr3a]];
>
> P1,…,Q1,… are dirac slashed values.
>
> Result should be zero, but in FeynCalc there is a bug with
calculating of
Tr[P1.P2.P3.GA[i].Q1.Q2.Q3.GA[i].GA[5])
term. The result contsins wrong imaginary combination of Levi-Civita
symbols (there are 15 terms instead of 6), real part is zero.
> So what is the reason for that?
> I can provide any files you might need.
>
> P.S. FeynCalc 8.2.0, Mathematica 9
>