Oneloop integral with gamma matrices

[rsato64]

• Your Mathematica version

  12.3.1 for Linux x86 (64-bit) (June 24, 2021)

• Your FeynCalc version

  9.3.1

• Did you try to reinstall FeynCalc (stable version) using the automatic installer to make sure that you have the latest bugfixes?

  Yes

• Does your Mathematica initialization file contain statements that might influence the behavior of FeynCalc? Sometimes external packages may modify `init.m` in unusual ways, causing troubles for other codes.

  (** User Mathematica initialization file **)

• Please provide a minimal working example that illustrates the problem and works on a fresh kernel. The example should be provided either by writing the code (as `InputForm`!) directly in the issue text or by attaching a Mathematica notebook. Please do not post code samples as screenshots, PDF files etc.: Those essentially require us to retype everything by hand, which is annoying and also time consuming. Please explain the difference between the current behavior and the expected behavior.

I have checked that the following oneloop integrals work properly in my environment. OneLoop[k, GSD[k] * FAD[{k,m},{k-p,m}] ] OneLoop[k, GSD[p] * FAD[{k,m},{k-p,m}] ] OneLoop[k, GSD[k].GSD[k] * FAD[{k,m},{k-p,m}] ] OneLoop[k, GSD[p].GSD[p] * FAD[{k,m},{k-p,m}] ]

But, this one loop integral does not work OneLoop[k, GSD[k].GSD[p] * FAD[{k,m},{k-p,m}] ] and I got error message like "DiracTrace::mixmsg: Expressions that mix D-, 4- and D-4-dimensional quantities are forbidden ... " I am wondering what an appropriate command to calculate oneloop integral with gamma matrices is.

[vsht]

A nonobvious fix would be to set FCSetDiracGammaScheme["BMHV"].

However, I would explicitly advise against using OneLoop in the first place, since this function is kept only for legacy reasons and is not really maintained anymore.

TID and PaVeLimitTo4 should provide equivalent results

TID[GSD[k] . GSD[p]*FAD[{k, m}, {k - p, m}], k, UsePaVeBasis -> True, 
 ToPaVe -> Automatic]
% // PaVeLimitTo4

https://feyncalc.github.io/FeynCalcBookDev/TID.html https://feyncalc.github.io/FeynCalcBookDev/PaVeLimitTo4.html

[rsato64]

Thanks a lot! It worked.