VBF dihiggs production in MadGraph

Asked by SOUMYA MUKHERJEE on 2018-12-26

 I am trying to produce VBF dihiggs production and the higgs decaying into bb~ and gamma gamma channel.
I used the following code.
-> define v = w+ w- z
-> import model heft
-> generate p p > h j j $v /a QED<=3 QCD<=0 HIW<=0 HIG<=0 , ((h > h1 h2) , h1 > a a HIW<=1 , h2 > b b~ QED<=1)
 this gives me the exact feynman diagrams but when I want to launch this, it gives
->Zero result detected: No Phase Space. Please check particle masses.

But I actually need this exact process. How I can fix this problem?
please help.

Question information

Language:
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Status:
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MadGraph5_aMC@NLO Edit question
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Last query:
2018-12-26
Last reply:
2018-12-27

Hi,

In my computer, your command crashes with:

Command "import /Users/omattelaer/Documents/workspace/2.6.5/cmd3" interrupted in sub-command:
"generate p p > h j j $v /a QED<=3 QCD<=0 HIW<=0 HIG<=0 , ((h > h1 h2) , h1 > a a HIW<=1 , h2 > b b~ QED<=1)" with error:
InvalidCmd : No particle h2 in model
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in 'MG5_debug'.
Please attach this file to your report.

Independently
Zero result detected: No Phase Space. Please check particle masses.

Is likely due to the fact that the "h" particle is not heavier than the sum of the mass of "h1" and "h2".
In that case Narrow-width approximation is not valid and neglecting other contribution is not save.

If you plan to include those contribution separately then you need to be very careful with the scale computation (and typically do not use the default dynamical scale choice of MG5aMC).
You might one to test to set the "bwcutoff" parameter of the run_card to a very high number to prevent the "onshell" cut.

Cheers,

Olivier

On 26 Dec 2018, at 21:12, SOUMYA MUKHERJEE <<email address hidden><mailto:<email address hidden>>> wrote:

define v = w+ w- z
-> import model heft
-> generate p p > h j j $v /a QED<=3 QCD<=0 HIW<=0 HIG<=0 , ((h > h1 h2) , h1 > a a HIW<=1 , h2 > b b~ QED<=1)

Dear Sir,
I found the actual problem in the subprocess h > h h , it gives the actual problem to continue the process. But in actuall dihiggs production in VBF there must be 3h- vertex . So is there any process or any specific model or any specific cuts for the on shell higgs to continue the process ?

Could you be more specific?

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________________________________
From: <email address hidden> on behalf of SOUMYA MUKHERJEE <email address hidden>
Sent: Thursday, December 27, 2018 7:38 AM
To: Olivier Mattelaer
Subject: Re: [Question #677043]: VBF dihiggs production in MadGraph

Question #677043 on MadGraph5_aMC@NLO changed:
https://answers.launchpad.net/mg5amcnlo/+question/677043

SOUMYA MUKHERJEE posted a new comment:
Dear Sir,
I found the actual problem in the subprocess h > h h , it gives the actual problem to continue the process. But in actuall dihiggs production in VBF there must be 3h- vertex . So is there any process or any specific model or any specific cuts for the on shell higgs to continue the process ?

--
You received this question notification because you are an answer
contact for MadGraph5_aMC@NLO.

Maybe what you are looking for is the following:

generate p p > h h j j QCD=0 HIW=0 HIG=0 , h > a a HIW<=1 , h > b b~

or

generate p p > h j j QCD=0 HIW=0 HIG=0 , h > a a b b~ HIW<=1

But I still have no clue of what you try to do...

Cheers,

Olivier

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