It indicates that your amplitude is not compatible with the chosen scheme for gamma^5, which is NDR by default. You could for example switch to BMHV
$BreitMaison=True;
In general, the choice of the gamma^5 scheme in chiral theories is a very subtle issue, so one should very well understand what one is doing. By understanding I mean not choosing some set of commands that makes the program spit out some answer, but having an idea how things work on pen and paper, what are the issues with gamma^5
in dim reg, why different schemes for g^5 exist and what are their advantages and disadvantages. Otherwise one cannot arrive to a sensible results.
Cheers,
Vladyslav
Am 6. Dezember 2016 09:59:33 MEZ schrieb Natthawin Cho <noreply@feyncalc.org>:
>I ran my program with FeynCalc and FeynArts package as following:
>
>1. Create Feynman diagram with `CreateTopologies` and `InsertFields`
>2. Get Feynman amplitude from `FCFAConvert[CreateFeynAmp[t2,...]`
>3. Simplify amplitude with `// Contract // DiracSimplify // DiracTrick
>// DiracEquation`
>4. Calculate loop integral with `OneLoop`
>
>The problem occurs at this step. I get
>
>DiracTrick::failmsg: "Error! DiracTrick has encountered a fatal problem
>and must abort the computation. The problem reads: Incorrect
>combination of dimensions and g^5 scheme!"
>
>How to solve this problem?
>
>Thanks.
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