**Next message:**Gilberto Tavares Velasco: "Possible bug in OneLoop"**Previous message:**Frederik Orellana: "Re: Problem using OneLoop"**In reply to:**Frederik Orellana: "Re: Problem using OneLoop"**Next in thread:**V. Shtabovenko: "Problem using OneLoop"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

Sorry for the typo. Should have been

amp = Pair[Momentum[k], Momentum[p1]]^3 FeynAmpDenominator[

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

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

p2), M]];

and yes, there does seem to be a problem. I will investigate it.

Frederik

Frederik Orellana wrote:

*> 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
*

*>> is the usual
*

*>>
*

*>> FYI: Tensor integrals of rank higher than 3 encountered; Please use the
*

*>> option CancelQP -> True or OneLoopSimplify->True or use another program.
*

*>>
*

*>> However, it appears that CancelQP->True is the default, and
*

*>> OneLoopSimplify
*

*>> expresses the results in terms of Contract3, which doesn't seem to exist.
*

*>>
*

*>> The integrals are box diagrams, and a typical term would look
*

*>> something like
*

*>>
*

*>> (k.p1)^3 / [k^2-lam^2][(k-q)^2-lam^2][(k-p1)^2-m^2][(k+p2)^2-M^2]
*

*>>
*

*>> where p1^2=m^2 and p2^2=M^2. This term looks innocent enough, and in fact
*

*>> looks to me like it IS of rank 3. By a lot of fudging and manipulating I
*

*>> managed to get a result using ScalarProductCancel, but it is hit and miss
*

*>> for various terms in the amplitude.
*

*>>
*

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

*>> if so,
*

*>> which one)?
*

*>
*

*>
*

**Next message:**Gilberto Tavares Velasco: "Possible bug in OneLoop"**Previous message:**Frederik Orellana: "Re: Problem using OneLoop"**In reply to:**Frederik Orellana: "Re: Problem using OneLoop"**Next in thread:**V. Shtabovenko: "Problem using OneLoop"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

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