Name: V. Shtabovenko Date: 05/27/19-07:04:59 PM Z
Hi,
sorry for the late reply. I think that the I gets inserted correctly,
although in the typesetting
is look wrong, cf.
FAD[{p, Sqrt[(Mchi^2 - I*Mchi*\[CapitalGamma]chi)]}]
FAD[{p, Sqrt[(Mchi^2 -
I*Mchi*\[CapitalGamma]chi)]}] //
PropagatorDenominatorExplicit
However, it is still not likely that you can get the correct result
with
ComplexConjugate:
If you look at
?ComplexConjugate
there is a clear warning that the denominators may not have imaginary
parts. But this is exactly what you are trying to do. So you would
need
some auxiliary function to make sure that the CC of the propagators
with
the I’s is taken correctly, otherwise the result is not going to be
consistent.
Cheers,
Vladyslav
Am 15.05.19 um 19:28 schrieb C. Sun:
> Dear Vladyslav and Mailing List Users,
>
> I got stuck by something probably very trivial. In short, I wonder
what is the elegant way to include the decay width in an internal
propagator. I have tried to implement it as
>
> (*after generating FA diagrams*)
> ruleResonance = {
> Mchi -> Sqrt[(Mchi^2 -
I*Mchi*\[CapitalGamma]chi)]
> };
> CreateFeynAmp[diagram] /. M$FACouplings /. ruleResonance
>
> However, after I apply FCFAConvert[], the minus sign is not
picked up right. I think that is because all other minus signs have been
wrapped as “-“ while the one I manually inserted in front of
\Gamma_{\chi} is just a regular minus sign. This causes trouble as
later when I do
>
> (amp[0] (ComplexConjugate[amp[0]])) //
> FermionSpinSum[#, ExtraFactor -> 1/2] & //
> DiracSimplify // Simplify// FCE // FeynAmpDenominatorExplicit
>
> all terms with decay width inserted are not simplified.
> Any input would be appreciated.
>
> Best,
> Chen
>