Name: gghuen Date: 07/10/19-05:42:57 PM Z
Hi,
I want to use FeynCalc to do some amplitude computation in Effective
Field Theories. In particular, I am interested in higher points
(𝑛>4) scattering amplitudes, that may receive contributions
from pure contact terms. When I create the topology for tree-level 3->3
processes, the result does not contain the topology of a contact term.
Instead, for a 2->2 process the contact term is considered in the
TopologyList. You can easily see this with the following commands
$LoadFeynArts = True;
«FeynCalc`;
$FAVerbose = 0;
FAPatch[PatchModelsOnly -> True]
top1 = CreateTopologies[0, 2 -> 2];
Paint[top1]
top2 = CreateTopologies[0, 3 -> 3];
Paint[top2]
Why contact terms of higher points amplitudes are not considered in the TopologyList? Indeed, when computing 6pt amplitudes, the 6pt contact terms of my model are not used while only 4pt contact terms are glued to make 6pt amplitudes.