off shell decay

Asked by Charlie on 2018-04-06

Dear MadGraph Team,

I am doing a calculation:

g g > h2 , (h2 > h3 z , (h3 > b b~, z > l+ l-))

I want h3 to be on-shell and z to be off shell here,.

If I use g g > h2, (h2 > l+ l- h3 , h3 > b b~)

there will be some diagrams I don't need.

What should I do? Thanks a lot!

Best!
Charlie

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2018-04-06
Last reply:
2018-04-06

Hi Charlie,

You can try the following syntax:
> g g > h2, (h2 > z > l+ l- h3 , h3 > b b~)

Note that since I have no clue of the model that you are using,
I'm not able to perform any check
 This is likely to produce only the Feynman diagram that you
ask for.
Note that the above syntax can break gauge (and consequently lorentz invariance)
so this is your responsability to check that the set of Feynman Diagram that you select is gauge invariant
both for the onshell and off-shell component. (off-shell Z typically need the associated photon contribution to be gauge invariant)

Cheers,

Olivier

> On 6 Apr 2018, at 09:53, Charlie <email address hidden> wrote:
>
> New question #667614 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/667614
>
> Dear MadGraph Team,
>
> I am doing a calculation:
>
> g g > h2 , (h2 > h3 z , (h3 > b b~, z > l+ l-))
>
> I want h3 to be on-shell and z to be off shell here,.
>
> If I use g g > h2, (h2 > l+ l- h3 , h3 > b b~)
>
> there will be some diagrams I don't need.
>
> What should I do? Thanks a lot!
>
> Best!
> Charlie
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Charlie (xianhui) said : #2

Dear Olivier,

Thanks for your kindly reply.
I will take care of that. By the way I have another question:

I am using an analysis code to analysis the delphes/pgs root file.
It works well with pgs root file, but wrong with delphes root file, I wonder is there any difference in the format of this two,
so that to cause the problem.

Best!
Xianhui
On 4/6/2018 16:09,Olivier Mattelaer<email address hidden> wrote:
Your question #667614 on MadGraph5_aMC@NLO changed:
https://answers.launchpad.net/mg5amcnlo/+question/667614

Status: Open => Answered

Olivier Mattelaer proposed the following answer:
Hi Charlie,

You can try the following syntax:
g g > h2, (h2 > z > l+ l- h3 , h3 > b b~)

Note that since I have no clue of the model that you are using,
I'm not able to perform any check
This is likely to produce only the Feynman diagram that you
ask for.
Note that the above syntax can break gauge (and consequently lorentz invariance)
so this is your responsability to check that the set of Feynman Diagram that you select is gauge invariant
both for the onshell and off-shell component. (off-shell Z typically need the associated photon contribution to be gauge invariant)

Cheers,

Olivier

On 6 Apr 2018, at 09:53, Charlie <email address hidden> wrote:

New question #667614 on MadGraph5_aMC@NLO:
https://answers.launchpad.net/mg5amcnlo/+question/667614

Dear MadGraph Team,

I am doing a calculation:

g g > h2 , (h2 > h3 z , (h3 > b b~, z > l+ l-))

I want h3 to be on-shell and z to be off shell here,.

If I use g g > h2, (h2 > l+ l- h3 , h3 > b b~)

there will be some diagrams I don't need.

What should I do? Thanks a lot!

Best!
Charlie

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

--
If this answers your question, please go to the following page to let us
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You received this question notification because you asked the question.

Hi,

That I do not know,
You should contact Delphes author about that.

Cheers,

Olivier

> On 6 Apr 2018, at 10:47, Charlie <email address hidden> wrote:
>
> Question #667614 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/667614
>
> Status: Answered => Open
>
> Charlie is still having a problem:
> Dear Olivier,
>
>
> Thanks for your kindly reply.
> I will take care of that. By the way I have another question:
>
>
> I am using an analysis code to analysis the delphes/pgs root file.
> It works well with pgs root file, but wrong with delphes root file, I wonder is there any difference in the format of this two,
> so that to cause the problem.
>
>
> Best!
> Xianhui
> On 4/6/2018 16:09,Olivier Mattelaer<email address hidden> wrote:
> Your question #667614 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/667614
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi Charlie,
>
> You can try the following syntax:
> g g > h2, (h2 > z > l+ l- h3 , h3 > b b~)
>
> Note that since I have no clue of the model that you are using,
> I'm not able to perform any check
> This is likely to produce only the Feynman diagram that you
> ask for.
> Note that the above syntax can break gauge (and consequently lorentz invariance)
> so this is your responsability to check that the set of Feynman Diagram that you select is gauge invariant
> both for the onshell and off-shell component. (off-shell Z typically need the associated photon contribution to be gauge invariant)
>
> Cheers,
>
> Olivier
>
> On 6 Apr 2018, at 09:53, Charlie <email address hidden>
> wrote:
>
> New question #667614 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/667614
>
> Dear MadGraph Team,
>
> I am doing a calculation:
>
> g g > h2 , (h2 > h3 z , (h3 > b b~, z > l+ l-))
>
> I want h3 to be on-shell and z to be off shell here,.
>
> If I use g g > h2, (h2 > l+ l- h3 , h3 > b b~)
>
> there will be some diagrams I don't need.
>
> What should I do? Thanks a lot!
>
> Best!
> Charlie
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
> https://answers.launchpad.net/mg5amcnlo/+question/667614/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/mg5amcnlo/+question/667614
>
> You received this question notification because you asked the question.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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