Name: Jon Palmer (email_not_shown)
Date: 04/27/04-06:59:58 PM Z


Rolf,

I am a bit confused by what the advantage of using an older version of
FeynArts would be. My research is on an extension of the Standard Model. I
have written the model file and tested it pretty extensively with FeynArts
both with and without FeynCalc. Me eventual goal is to do two loop self
energy calculations on my model. At the moment I am just trying to do one
loop calculations as a test of the FeynCalc method (the one loop results
have previously been done by hand).

I have attached a mathematica notebook with the type of self energy
calculation I need to do. It was a test of the method I did for the electron
self energy in QED, using FeynCalc 4.1.1. The last two calculated terms can
be combined for the standard result of the QED one loop mass correction. I
am not sure how I would use FeynCalc5 beta1 and the createFeynAmp function
to do the same calculation in terms of PV functions. Would you have any
suggestions?

Many thanks,
Jon Palmer

> -----Original Message-----
> From: Rolf Mertig [mailto:rolf@mertig.com]
> Sent: Monday, April 26, 2004 9:20 PM
> To: Jon Palmer
> Cc: 'Frederik Orellana'; feyncalc@feyncalc.org
> Subject: Re: FeynCalc5 Beta1
>
> 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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