Name: Marco Rocco (email_not_shown)
Date: 05/30/17-11:00:42 AM Z


Hi,

When I run this on FeynCalc 9.2.0:

GAD[\[Rho]].(GSD[k] + GSD[q] + M).GAD[\[Mu]] .GAD[\[Rho]].(GSD[k] -
    GSD[p] + m).GAD[\[Mu]];
num = DiracSimplify[%] // FullSimplify;

amp = num FeynAmpDenominator[
   PropagatorDenominator[k + q + r, SmallVariable[\[Lambda]]],
   PropagatorDenominator[k + q, M],
   PropagatorDenominator[k, SmallVariable[\[Lambda]]],
   PropagatorDenominator[k - p, m]]

SetOptions[OneLoop, Dimension -> D];

res = (-I/Pi^2) OneLoop[k, amp] // FullSimplify

I get this message from OneLoop:

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!

but I don't know why, since my calculations don't involve g^5 and it seems to me to use a correct combination of dimensions.

If I rewrite the numerator already simplified by DiracSimplify without "." (Dirac dot) between DiracSlash, I don't get the message and FC starts running. Anyway, I don't know if the final result is correct without ".".

Could someone explain to me what's happening?

Thanks a lot,
Marco



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