Hi,
in general, there can be many reasons why the result does not come out
right and from my experience only in a very small amount cases that can
be attributed to bugs in FeynCalc itself.
The H-> 2 g decay via a top loop is acutally included as an example for
the FeynHelpers addon
<https://github.com/FeynCalc/feynhelpers/blob/stable/Examples/EW/EWHiggsToTwoGluonsOneLoop.m>
and there it precisely reproduces the result from the literature. So
may be you should study it first.
I don't know what exactly you mean with annotations for PaVe being gone.
The feyncalc.github.io/reference page has not really changed since 2016.
Cheers,
Vladyslav
Am 27.05.19 um 14:33 schrieb Pengfu Tian:
> dear developers:
> I did a calculation about quark loop contribution to the process of Higgs decay to gluons.
> There are two questions that I want to ask.
> the 1st is that mathematica is always warning me about "PolarizationSum::notmassless: Warning! You are inserting a polarization sum for massless vector bosons, but the momentum of the external boson Subscript[p, 1] is not on-shell. Please put it on-shell via ScalarProduct[Subscript[p, 1],Subscript[p, 1]]=0" but actually I've done onshell definition in the bigining.
> the 2nd one is that the result of my calculation is
> "(\[Alpha]
> \!\(\*SubsuperscriptBox[\(m\), \(q\), \(4\)]\)
> \!\(\*SubsuperscriptBox[\(\[Alpha]\), \(s\), \(2\)]\) (\!\(
> \*SubsuperscriptBox[\(m\), \(h\), \(2\)] - \(4\
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)]\)\))^2 \!\(TraditionalForm\`
> \*SubscriptBox[\("C"\), \("0"\)](0, 0,
> \*SubsuperscriptBox[\(m\), \(h\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)])\)^2)/(4 \[Pi]^2
> Subscript[m, h]
> \!\(\*SubsuperscriptBox[\(m\), \(W\), \(2\)]\)
> \!\(\*SubsuperscriptBox[\(s\), \(W\), \(2\)]\))"
>
> but actually the result should be
>
> "(\[Alpha]
>
> \!\(\*SubsuperscriptBox[\(m\), \(q\), \(4\)]\)
>
> \!\(\*SubsuperscriptBox[\(\[Alpha]\), \(s\), \(2\)]\) ((\!\(
> \*SubsuperscriptBox[\(m\), \(h\), \(2\)] - \(4\
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)]\)\))^2 \!\(TraditionalForm\`
> \*SubscriptBox[\("\<C\>"\), \("\<0\>"\)](0, 0,
> \*SubsuperscriptBox[\(m\), \(h\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)],
> \*SubsuperscriptBox[\(m\), \(q\), \(2\)])\) - 2)^2)/(4 \[Pi]^2
> Subscript[m, h]
>
> \!\(\*SubsuperscriptBox[\(m\), \(W\), \(2\)]\)
>
> \!\(\*SubsuperscriptBox[\(s\), \(W\), \(2\)]\))"
>
> In fact，some annotaion about Functions related to "PaVe" on page https://feyncalc.github.io/reference are gone.
> Are those functions whose annotation have disappeared just be abandoned?
>
> Thanks for your help!
> Best regards!
> Pengfu Tian
>
This archive was generated by hypermail 2b29 : 09/04/20-12:55:05 AM Z CEST