Dear FeynCalc users,
in the last weeks I spent quite some time to refactor DiracTrace and
DiracTrick making trace computation in different schemes more consistent
and a bit faster.
DiracSimplify has not been optimized yet, but I'm looking into it. I
would like to ask you to test the new changes (via the development
version) and report bugs or inconsistencies. In general, now there are a
lot of cross checks to ensure the consistency of the calculation and
some of them might be too restrictive leading to false positives.
Also there is an important change in TID. From now on, it will not
accept input with mixed dimensions like FV[q, mu] FVD[q, nu] FAD[{q,
m}], unless you are using BMHV scheme for gamma5, where such objects
indeed can occur. Until now, TID would silently apply ChangeDimension to
convert such input into fully D-dimensional objects.
However, the point is that in dim reg you really should use
D-dimensional amplitudes, unless the t'Hooft-Veltman scheme is used,
where the mixture of objects in 4, D and D-4 dimensions is unavoidable.
The permissive behavior of TID turned out to be a source of errors like
here
http://www.feyncalc.org/forum/1115.html
that really should not happen. So please use FVD, GAD, GSD and SPD to
input your D-dim amplitudes.
Cheers,
Vladyslav
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