Name: Frederik Orellana (email_not_shown)
Date: 04/19/03-03:26:43 PM Z


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)?
>
>



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