Replies: 2 comments 12 replies
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As a quick idea (I didn't look at the code yet) you may try
BTW, I had an idea of a proper LoopTools interface via FeynHelpers, https://github.com/FeynCalc/feynhelpers/blob/looptools/Interfaces/LoopTools.m If you are interested, I could try to revamp it over the weekend. |
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Hello @vsht , sorry to open again this old discussion. I need to evaluate numerically some B0,C0,D0 functions obtained through Feyncalc. I downloaded the development version of FeynHelper, however it is not working on my system, I think because I am on Windows. |
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For background - I am attempting to numerically compute one loop amplitude contributions in the mass insertion approximation for a one-to-three decay process. To get a feel for the algorithm I am computing the decay rate for just one diagram. My idea was to use FeynCalc's
TID
function to first rewrite the amplitude (which I have written out explicitly) in terms of Passarino-Veltman scalar integrals and then use the following substitution ruleto evaluate these functions numerically using LoopTool's. This seems to work as expected, after substituting the relevant numerical factors I end up with a lengthy summation of spinor-gamma matrix blocks. The next natural step, in my mind, is to obtain the spin-averaged squared amplitude using the
FermionSpinSum
function. Upon doing so I seem to run into an infinite loop with errorsI have been unable to find a solution to this problem. My thought is that maybe FeynCalc's internal language is getting tangled when I evaluate PaVe's with LoopTools. I have not been able to find the origin of the
OptionQ[...]
even after looking at the stack.I have attached a notebook which contains my code. If you have any suggestions/corrections/comments on my implementation they would be much appreciated. Also, if you need any other information let me know.
I am using Mathematica 12.1 with FeynCalc 9.3.1 and LoopTools 2.15 on a Manjaro system.
recursiveErrorBoxDiagram.zip
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