Name: Rolf Mertig (email_not_shown)
Date: 04/26/04-10:19:33 PM Z


Well ..., it is a bit of a hack, but seems to give something sensible:

<< HighEnergyPhysics`FeynCalc`

t11 = CreateTopologies[1, 1 -> 1, Adjacencies -> {3}];
graf = InsertFields[t11, V[1] -> V[1],
      Restrictions -> {QEDOnly,
        NoGeneration2, NoGeneration3}, ExcludeParticles -> {F[3 | 4]},
          InsertionLevel -> Classes ];

test = Factor2[OneLoopSimplify[q1,
    DotSimplify[ChangeDimension[CreateFeynAmp[graf, Truncated ->
True][[1,3]] /.
             NonCommutative -> Dot /. MatrixTrace -> DiracTrace /.
Mass[_] :> MLE /.
          FourMomentum[Internal, 1] -> q1 /. FourMomentum[Outgoing, 1]
-> p, D] /. Times -> Dot] /.
     DiracTrace -> TR]]

Notice that those FeynArts - models are made for FormCalc.
You might also want to experiment with ToFA1Conventions
Or just use an older FeynArts version. Some 10 years ago FeynArts was
easier to use for certain problems ...
Maybe I dig out an old version with old model files (for QED and QCD).
I tried to simulate the old behaviour with the new FCQCDLorentz and
FCQCD model files, but I think I got stuck somewhere with
MatrixTrace and internal loops and combinatorical factors and so on.
Maybe someone else wants to go on with this? (unfortunately I do not
have much time for this right now).

I think that Frederik's CreateFCAmp function should actually be there
somewhere. It was indeed useful.

--
You may also just insert the Feynman rules "by hand", like there 
examples in the Amplitudes.m file.
This way you see what is going on.
--

Rolf

Jon Palmer wrote:

>Dear Rolf, > >Ok so createFeynAmp does work but I'm not sure how to process the results. >The calculation that I am trying to do is similar to that found in >http://www.feyncalc.org/forum/att-0099/01-QED_SM.nb > >Could you explain how the same calculation could be done using >CreateFeynAmp? > >Many thanks >Jon Palmer > > > > > >>-----Original Message----- >>From: Rolf Mertig [mailto:rolf@mertig.com] >>Sent: Monday, April 26, 2004 6:35 PM >>To: Jon Palmer >>Cc: Frederik Orellana >>Subject: Re: FeynCalc5 Beta1 >> >>Dear Jon, >>CreateFeynAmp (from FeynArts) should be enough. Check out the examples >>in the fcexamples directory. >> >>I am not sure but I think we had some trouble with the CreateFCAmp >>function, Frederik? >> >>Rolf >> >>Jon Palmer wrote: >> >> >> >>>Dear Rolf, >>> >>>Great news that the beta of feyncalc5 is out and seems to have the >>>Mathematica 5/PHI issue worked out. However I was wondering what has >>>happened to the CreatFCAmp function? It no longer seems to be >>> >>> >>implemented. >> >> >>>Has it just been renamed as something else and if so how is it now used? >>>I've tried to search the help but it doesn't appear to have much >>> >>> >>information >> >> >>>on the issue. >>> >>>Thanks for you help, >>> >>>Jon Palmer >>> >>> >>> >>> >>> >>> >>> > > > > >



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