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Hello,

I tried to find a general expression for a tensor integral using

Feyncalc. To test the result, I performed an especially easy

contraction where one can calculate the result by hand. Unfortunately

I reproduced the result only up to an additional summand of 1/2.

I then tried to find where I made a mistake. Finally I figured out

that there is obviously a problem with Feyncalc. Maybe it is related

to Bug #4, but it is somehow different.

Using the following mathematica code, the problem becomes obvious

already in this very simple case:

LoopFunc =

FVD[q, \[Mu]] FVD[q, \[Nu]]

FAD[{q, Subscript[m, 0]}, {q + Subscript[p, 1], Subscript[m, 1]}]

test1 =

OneLoop[q,

Contract[MTD[\[Mu], \[Nu]] LoopFunc ,

OneLoopSimplify -> False] ]

test2 = Contract[

MTD[\[Mu], \[Nu]] OneLoop[q, LoopFunc,

OneLoopSimplify -> False] ]

diff = PaVeReduce[(test1 - test2)]

Can you please comment on this. Maybe it is already known. Or you can

advice me, what I should not do using these functions since I do not

know why this problem occurs.

best regards,

Sascha

**Next message:**mariam: "FORTRAN 77/90 to Mathematica"**Previous message:**karima: "FeynArts, FeynCalc and Looptools."**Next in thread:**Vladyslav Shtabovenko: "Re: Additional Bug to #4 in OneLoop or PaVeReduce?"**Maybe reply:**Vladyslav Shtabovenko: "Re: Additional Bug to #4 in OneLoop or PaVeReduce?"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

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