Name: Frederik Orellana Date: 04/19/03-03:14:47 PM Z
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)?