Dear All,
Can anyone enlighten me as to how to handle complex infinities that arise in tadpole diagrams involving massless particles? For instance the following calculation in QED:
tops = CreateTopologies[1, 1 -> 1];
ins = InsertFields[tops[[2]], F[1, {1}] -> F[1, {1}], Model -> QED,
InsertionLevel -> {Particles}];
CreateFeynAmp[ins]
Produces three diagrams whose amplitudes involve 'ComplexInfinity' due to the zero mass of the photon. How should these diagrams be handled by FeynArts/FeynCalc?
Many thanks
Jon
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