MadGraph5_aMC@NLO

generate g g > h > z h, z > b b~, h > a a

Asked by yinxinyue

I want to generate g g > h > z h, z > b b~, h > a a in model heft, but have some error:
generate g g > h > z h, z > b b~, h > a a
INFO: Checking for minimal orders which gives processes.
INFO: Please specify coupling orders to bypass this step.
INFO: Trying process: g g > h > z h HIG<=1 HIW<=1 WEIGHTED<=4 @1
Command "generate g g > h > z h, z > b b~, h > a a" interrupted with error:
NoDiagramException : No amplitudes generated from process Process: g g > h> z h HIG=1 HIW=1 WEIGHTED=4 @1
   Decay: z > b b~
   Decay: h > a a. Please enter a valid process
what should i do to generate the process

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

The "HHZ" vertex is not part of the HEFT model (makes sense since MZ+MH> MT, so you can not use the infinite top mass limit.

> g g > h > z h

Additionally this is going to be a two loop computation without proper factorization, so I do not think that HEFT would work here.

So here you can not use HEFT, and we can not compute two-loop amplitude.
So I do not see a clear way to do what you ask.

Cheers,

Olivier

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yinxinyue (yinxinyue0420) said : 		#2

Thanks, and I have question about how to generate Higgs quartic self-coupling. I try to use madgraph generate g g > h > h h h,but only one process that i need in all process. Is there any other command that can generate only one process?

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Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

Again the heft should not be used for such production (the infinite top mass limit is not valid if the produced higgs from ggh vertex is that far offshell.

So for such process, the best is to use the loop induced mode.
For loop computation, you can use the loop-filtering feature (that you have to code yourself) but my advise would be that you generate a new UFO model where the Higgs does not have a triple point interaction), you should be able to do that with FeynRules and NLOCT.

If you really want to use heft, then you can use the diagram filtering option (again you will have to code it yourself) or you can probably tweak the UFO model by hand and remove the three point interaction that you do not want to have.

Cheers,

Olivier

> On 6 Jan 2023, at 16:00, yinxinyue <email address hidden> wrote:
>
> Question #704308 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/704308
>
> Status: Answered => Open
>
> yinxinyue is still having a problem:
> Thanks, and I have question about how to generate Higgs quartic self-
> coupling. I try to use madgraph generate g g > h > h h h,but only one
> process that i need in all process. Is there any other command that can
> generate only one process?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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yinxinyue (yinxinyue0420) said : 		#4

Thank you very much for your answer, I will try to generate a new model.

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