MadGraph5_aMC@NLO

I want to generate gg -> H -> hh and I'm using heft model for the MadGraph5

Asked by seve

Hi dear all.

I want to generate gg -> H -> hh in the 2HDM model, but in 2HDM model the process gg->H is not implemented, so I use heft model, but I only get an error. I'm using MadGraph5 version 2.2.1.

MG5_aMC>import model heft
INFO: Restrict model heft with file models/heft/restrict_default.dat .
INFO: 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
Defined multiparticle all = g u c d s u~ c~ d~ s~ a ve vm vt e- mu- ve~ vm~ vt~ e+ mu+ t b t~ b~ z w+ h h1 w- ta- ta+
MG5_aMC>generate g g > h1 > h h
INFO: Checking for minimal orders which gives process es.
INFO: Please specify coupling orders to bypass this step.
INFO: Trying process: g g > h1 > h h WEIGHTED=4 HIW=1 HIG=1
Command "generate g g > h1 > h h" interrupted with error:
InvalidCmd : No amplitudes generated from process Process: g g > h1> h h HIG=1 HIW=1 WEIGHTED=4. Please enter a valid process

This is similar to Question #238615: Is the heft_v4 model and the heft-full model similar?

Thanks a lot in advance.
Severiano.

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
Federico Demartin Edit question
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Last reply:
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Federico Demartin (federico-demartin) said : 		#1

Hi Severiano,

I was assigned to this question even though I haven't built any of the two models you mention, so I cannot help you too much.

From what I can see, in the 2HDM the ggH interaction is not implemented (as you said), and in the heft model the Hhh interaction is not implemented. So, in both cases, you ask to generate an amplitude that the model you load cannot generate.

It should be straightforward to ask one of the authors of those models to implement the missing interaction that you need.
Olivier, can you reassign this question to an author of the heft model or the 2HDM model?
Cheers,

Federico

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#2

Hi Severiano,

In the 2HDM, this is a loop induce process, which will be available by the end of the year. I don't know any good model which contracts the loop to an (approximate) effective vertex like that his the case for the standard model. So I'm afraid that we do not have any generic solution for the 2HDM.

One possibility might be possible if one of your Higgs is exactly sm like. Then it might be possible to trick MG to make it work by doing the following:
import model 2hdm
add model hgg_plugin
This command will create a new model with the original 2hdm model with on top of it the top-loop contracted diagram haa and hgg.
The expression of those vertex are those for the Standard Model. Be careful that, at least, you can not use that for all benchmark point. I'm actually not 100% sure that you can use that for any benchmark point, so please check carefully if what you are doing makes sense or better wait for the version 2.3 of MG5_aMC.

Concerning the heft model. The purpose of that model is to be SM only, so I do not think that it fit what you need.

Cheers,

Olivier

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