Model import fails

Asked by Maksym Ovchynnikov on 2019-06-20

I have a Chern-Simons-Portal.fr file containing the following:

M$ClassesDescription = {
V[4] == {
ClassName -> xb,
SelfConjugate -> True,
Mass -> {Mxb, 1},
ParticleName -> "~xb"}
}

M$Parameters = {
cW == {
Value -> 0.001,
InteractionOrder -> {QED, 2},
Description -> "X boson coupling to W bosons"},

cmu == {
Value -> 1,
InteractionOrder -> {QED, 2},
Description -> "X boson coupling to muons"}
}

I generate the model using the following code in Mathematica:

LoadModel["SM.fr", "Chern-Simons-Portal.fr"]
LoadRestriction["Massless.rst", "DiagonalCKM.rst"]
LCS := cW Eps[\[Mu], \[Nu], \[Alpha], \[Beta]] W[\[Mu]] xb[\[Nu]] del[
    HC[W[\[Alpha]]], \[Beta]] +
  cW Eps[\[Mu], \[Nu], \[Alpha], \[Beta]] HC[W[\[Mu]]] xb[\[Nu]] del[
    W[\[Alpha]], \[Beta]] + xb[\[Nu]] mubar.Ga[\[Nu]].Ga[5].mu +
  Mxb^2/2 xb[\[Nu]] xb[\[Nu]] -
  1/4 (del[xb[\[Mu]], \[Nu]] -
     del[xb[\[Nu]], \[Mu]]) (del[xb[\[Mu]], \[Nu]] -
     del[xb[\[Nu]], \[Mu]])
WriteUFO[LCS];

I do not have any warnings or errors during running the code. However, after opening a file parameters.py I see that the width of xb particle is defined twice:

Wxb = Parameter(name = 'Wxb',
                nature = 'external',
                type = 'real',
                value = 1,
                texname = '\\text{Wxb}',
                lhablock = 'DECAY',
                lhacode = [ 9000006 ])

Wxb = Parameter(name = 'Wxb',
                nature = 'external',
                type = 'real',
                value = 1,
                texname = '\\text{Wxb}',
                lhablock = 'DECAY',
                lhacode = [ 9000001 ])

When importing the model in MadGraph is have the following error:

Error detected in "import model ChernSimons_UFO"
write debug file MG5_debug
If you need help with this issue please contact us on https://answers.launchpad.net/mg5amcnlo
InvalidModel : name Wxb define multiple time. Please correct the UFO model!

I tried simply to remove the extra lines for the decay width, but the error remained. Where can be a reason?

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2019-06-20
Last reply:
2019-06-20

Hi,

I guess that you should contact the Feynrules author about that.
Looks like that you have two different particles with the same width
(particle 9000006 and 9000001). I guess that in your definition of those particles in FR, if you ask for different width it should fix your issue. (But do not ask me how to do that since I have close to zero experience in FR)

If you remove one of the lines, I guess that you will have another crash, don't you?

Cheers,

Olivier

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