NMSSM Higgs syntax problem

Asked by kyle on 2012-03-02

Hello,

I have been attempting to create events for a Higgs decay in the NMSSM model. The decay is pp > W+H0, H0 > a a, a > mu mu, where H0 is the neutral Higgs of 125GeV and a is a lighter Higgs with mass of 9GeV. Looking at the particle lists under the nmssm model, I can see that it lists the desired particle (It isn't the exact same mass, but I can change the mass to what I like), but when I input a01, it says "no particle a01 in model". It clearly is in the model, but does not register it. The lists can be found in within the /model/nmssm/particle.py. Is there another letter that represents this higgs?

-Kyle Tos

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MadGraph5_aMC@NLO Edit question
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Last query:
2012-03-02
Last reply:
2012-03-02

Hi Kyle,

By default, MG5 overwrites the name of a couple of particles, such that they have the same name in all models.
If you want to use the name defined in the UFO model, you can use the command
import model NMSSM --modelname

If you want to modify the list of particles which are overwritten by MG5, you can edit the files:
input/particles_name_default.txt

Cheers,

Olivier

kyle tos (kyletos88) said : #2

Thank you for the quick response. I did import the model, but the question then is why there is no section for the NMSSM in the input particle list? I can't use the ones defined for MSSM because the values for the mass of the higgs are different for NMSSM and MSSM. And how do I add to it? Does simply writing a particle into the list make the program register it when a process is generated?

Thank you again for responding so quickly.

-Kyle

kyle tos (kyletos88) said : #3

Thank you for the quick response. I did import the model, but the question then is why there is no section for the NMSSM in the input particle list? I can't use the ones defined for MSSM because the values for the mass of the higgs are different for NMSSM and MSSM. And how do I add to it? Does simply writing a particle into the list make the program register it when a process is generated?

Thank you again for responding so quickly.

-Kyle

Hi Kyle,

Not sure to understand your point, in the last post.
So let me try to explain a bit more

mg5>import model nmssm
models.import_ufo: Restrict model nmssm with file models/nmssm/restrict_default.dat .
models.import_ufo: Run "set stdout_level DEBUG" before import for more information.
INFO: Change particles name to pass to MG5 convention
Kept definitions of multiparticles l- / j / vl / l+ / p / vl~ unchanged
mg5>display particles
Current model contains 51 particles:
w+/w- x1+/x1- x2+/x2- h+/h- ve/ve~ vm/vm~ vt/vt~ e-/e+ mu-/mu+ ta-/ta+ u/u~ c/c~ t/t~ d/d~ s/s~ b/b~ sve/sve~ svm/svm~ svt/svt~ el-/el+ mul-/mul+ ta1-/ta1+ er-/er+ mur-/mur+ ta2-/ta2+ ul/ul~ cl/cl~ t1/t1~ ur/ur~ cr/cr~ t2/t2~ dl/dl~ sl/sl~ b1/b1~ dr/dr~ sr/sr~ b2/b2~
a z g n1 n2 n3 n4 n5 go h01 h2 h03 h3 a02

While if i do:

mg5>import model nmssm --modelname
models.import_ufo: Restrict model nmssm with file models/nmssm/restrict_default.dat .
models.import_ufo: Run "set stdout_level DEBUG" before import for more information.
Kept definitions of multiparticles l- / j / vl / l+ / p / vl~ unchanged
mg5>display particles
Current model contains 51 particles:
w+/w- x1+/x1- x2+/x2- h+/h- ve/ve~ vm/vm~ vt/vt~ e-/e+ mu-/mu+ tau-/tau+ u/u~ c/c~ t/t~ d/d~ s/s~ b/b~ sv1/sv1~ sv2/sv2~ sv3/sv3~ sl1-/sl1+ sl2-/sl2+ sl3-/sl3+ sl4-/sl4+ sl5-/sl5+ sl6-/sl6+ su1/su1~ su2/su2~ su3/su3~ su4/su4~ su5/su5~ su6/su6~ sd1/sd1~ sd2/sd2~ sd3/sd3~ sd4/sd4~ sd5/sd5~ sd6/sd6~
a z g n1 n2 n3 n4 n5 go h01 h02 h03 a01 a02

and with the last syntax, you see that a01 is now defined.

For the files input/particles_name_default.txt. This is use only if you don't put the --modelname.
So you don't probably need to modify it. (At least in most of the cases)

Cheers,

Olivier

kyle tos (kyletos88) said : #5

Thank you. That fixes that problem. Two more questions:

1) What does the "-modelname" do?

2) If there is a process that does not exists, is there a way for me to create it and then run events of that process? For instance, I am getting this error:

  MadGraph5Error : No amplitudes generated from process Process: a01 > mu- mu+ WEIGHTED=4. Please enter a valid process.

I noticed a file called MadGraph5/model/nmssm/vertices.py . Can I defined vertices for this process, or would it be much more involved than a simple definition?

-Kyle Tos

Hi Kyle,

> 1) What does the "-modelname" do?

It keeps the name of the particles untouched (i.e. it uses the names defined in the UFO model in the files particles.py)
when you don't specify this options, we checked for the particles if the pdg number correspond to one of the entry of
the files input/particles_name_default.txt and if so we replace the name of the particles by the one present on the same line.

> 2) If there is a process that does not exists, is there a way for me to create it and then run events of that process? For instance, I am getting this error:

One possibility is off course to add the interaction by hand, The difficult part is off course to define the lorentz structure in a correct way (if the lorentz structure is the same has another vertex, then this might be a possible option). So this is at least not trivial to do.

The best way is probably to install FR on your computer, and recreate the model by adding in the Lagrangian the corresponding term.
You will find all the files used for the creation of this model at the following pages:
http://feynrules.irmp.ucl.ac.be/wiki/NMSSM
If you need help for doing that you can probably directly send a mail to Benjamin (you will find contact information in the above link)

Cheers,

Olivier

kyle tos (kyletos88) said : #7

Thank you very much. I will work on this and then get back to you. I really appreciate the help. Have a good weekend.

-Kyle

kyle (kmtos) said : #8

So, I tried the first option of defining the interaction by hand. I found a different lorentz structure that is the same as the one needed for the vertex that I'm trying to create. So I simply created a the vertex and used the same structure, but renamed the names from tau -> mu. This creates another problem though. When I type in the "import model nmssm -modelname" I get this error:

Command "import model nmssm -modelname " interrupted with error:
IndentationError : unexpected indent (vertices.py, line 6127)

Is there something else that I need to do after simply naming a new verex? Is there another file I need to change? Could it be a problem with the couplings?

Thank you,
Kyle

kyle (kmtos) said : #9

Hahaha. Nevermind, I saw what was wrong. There was a space and there shouldn't be one. I stared at it for a long while and never noticed. It's fixed. Sorry to bug you.

Kyle

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