MadGraph5_aMC@NLO

Questions about generating pp>h+>w h2 and pp>h3>z h2

Asked by Zhiyuan

Dear MG experts,

I am new to Madgraph and I have two questions (if I may!) that I would like your advice on:

1. I am trying to produce this process:
generate p p > h+ > w+h2

I started with 2HDMtII_NLO, but it returned an error:
```NoDiagramException : No amplitudes generated from process Process: g/u/c/d/s/u~/c~/d~/s~ g/u/c/d/s/u~/c~/d~/s~ > h+> h2 w+ WEIGHTED=8 @1. Please enter a valid process```

I saw on CMS genproductions GitHub that, in some ChargeHiggs production cards, the 2HDMtII_NLO is used, and the charged Higgs is generated associated with t/b quarks. I have tested generating using these data cards myself and it does work. However, in my analysis, we are interested in the final state of Vhh (with the h2 decaying to two SM higgs), so production with t/b is not of our interest.

Is this process valid in Madgrah? If so, is there a model you would recommend using?

P.S. I tried using 2HDM_UFO and this process generates smoothly and produces seemingly valid output.

2. I am also generating an pp> h3> z h2 process, using some existing data cards. These cards have different mass values of h3 and h2, and assigning specific values of higgs 1 and higgs 2 parameters for each mass point. For example, for m_h3 = 1500, m_h2=400, there is:
set param_card higgs 1 -34.88251
set param_card higgs 2 34.82759
I wonder what is the meaning of these parameters, and how one can determine these parameter values, suppose we want to generate different mass points?

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

I actually do not know those models.
What I can say is to look at what is inside the model and explained what is the difference between the two model
In 2HDMtII_NLO, the charged Higss only couple to the third generation while in the 2HDM model, I do have that particle that interact with the three generation.

This explains why you do not have any diagram generated via 2HDMtII_NLO model while you have some for the second model.
And seems consistent with your observation of what CMS is doing.

>I wonder what is the meaning of these parameters, and how one can determine these parameter values, suppose we want to generate different mass points?

Here you should check the documentation of the model to see the parametrization that they use.
This block is likely related to the Higgs potential, but I do not know enough such type of model to give a better answer.

Cheers,

Olivier

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