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Hello.

I tried to reproduce this behaviour. An integrand corresponding to what

you write would be:

amp = Pair[Momentum[k], Momentum[p1]]FeynAmpDenominator[

PropagatorDenominator[k, lam], PropagatorDenominator[(k - q), lam],

PropagatorDenominator[(k - p1), m], PropagatorDenominator[(k +

p2), M]];

With this,

OneLoop[k, amp]

evaluates without problems.

I need more details in order to help: Your integrand in FeynCalc

notation; the version of FeynCalc you're using.

Frederik

Peter Blunden wrote:

*> I'm trying to do an integral that FeynCalc chokes on. The message returned
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*> is the usual
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*>
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*> FYI: Tensor integrals of rank higher than 3 encountered; Please use the
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*> option CancelQP -> True or OneLoopSimplify->True or use another program.
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*>
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*> However, it appears that CancelQP->True is the default, and OneLoopSimplify
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*> expresses the results in terms of Contract3, which doesn't seem to exist.
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*>
*

*> The integrals are box diagrams, and a typical term would look something like
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*>
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*> (k.p1)^3 / [k^2-lam^2][(k-q)^2-lam^2][(k-p1)^2-m^2][(k+p2)^2-M^2]
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*>
*

*> where p1^2=m^2 and p2^2=M^2. This term looks innocent enough, and in fact
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*> looks to me like it IS of rank 3. By a lot of fudging and manipulating I
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*> managed to get a result using ScalarProductCancel, but it is hit and miss
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*> for various terms in the amplitude.
*

*>
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*> Is there a fix in FeynCalc, or do I have to use another program (and if so,
*

*> which one)?
*

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