Di Higgs production using MSSM model in MG5_aMC@NLO

Dear Aya,

Tools are existing in order to generate UFO model (the input format for model)
you can check
FeynRules
Sarah
LanHep

I'm not familiar with any of them actually and therefore can not help for generating a new model.

Now the first question is how you want to generate that?
For the SM a reasonable approximation is to take the infinite top-mass limit.
(i.e. the particle running in the loop being much more massive than the mass of the Higgs).
This might be something that you can consider here as well.
In that case the g gh02 is a tree-level interactions and you can use the syntax:
generate g g > h2, h2 > h01 h01, h01 > b b~, h01 > z z

If the above does not fit your need, then you need to have a UFO model that is able to compute loop matrix-element. (Some SUSY model already exist but I do not know if they can compute such loop so please check the literature on that, in particular: http://feynrules.irmp.ucl.ac.be/wiki/MSSMatNLO).

In that case the method to generate your process would be
generate g g > h2 [QCD]
output
launch
MadSpin=none
decay h2 > h01 h01, h01 > b b~, (h01 > z z)

Cheers,

Olivier

PS: I assume here that h2 is onshell

> On 13 Feb 2020, at 12:44, Aya Ismail Hosny Beshr <email address hidden> wrote:
>
> New question #688734 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/688734
>
> Hi,
>
> I have an issue please! I am trying to produce this process: p p > g g > h2 > h01 h01, h01 > b b~, (h01 > z z) in which I need to study the ggF production mode to produce a Heavy Neutral Higgs (H) that is described in the MSSM model, which is then going to decay into lighter SM like higgs (h h). The problem is I have tried for various versions of MG5@NLO to produce this process via the MSSM models available within MG, but nothing is working. Actually, I am doing experimental particle physics and I am new to all this. So is it needed to have or build a new model and implement it within MG to solve this issue? In that case should I kindly request the MG5 team to make one please? or how could I solve this? Sorry, I am new to the field!
>
> Appreciating your time!
>
> Best Regards,
> Aya
>
> --
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Dear Olivier,

Thanks for our kind reply! I will try to generate a new model.

Yes, actually I am trying to generate this process including the heavy quark loop (e.g: Top ) responsible for generating h2 for BSM study, I am not dealing with the tree level case. No, I have tried those models they can't compute the loop matrix-element.
Thanks a lot for your help I will try what you have mentioned.

Best Regards,
Aya

This what I have tried for MSSM_SLHA2 model as an example and the error appeared is mentioned.

MG5_aMC>generate g g > h2 [QCD]
The current model MSSM_SLHA2 does not allow to generate loop corrections of type ['QCD'].
Command "generate g g > h2 [QCD]" interrupted with error:
InvalidCmd : The model MSSM_SLHA2 cannot handle loop processes