Name: Rolf Mertig (email_not_shown)
Date: 04/28/04-10:07:34 PM Z


Jon,
my point is that the new FeynArts is sometimes more complicated than
necessary. But one
can work with it.
See my variation of your notebook.
Rolf

Jon Palmer wrote:

>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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