Requested events not being processed

Asked by SUBHASISH BEHERA on 2020-07-23

Dear Olivier,

I was trying to generate the following process :
generate .. > .. , h > all all all all $all QED<=99
It is a process with single Higgs production, which will further decay to 4-particles.
The process would have 1380 diagrams.

In fact I was trying to produce inclusive Higgs decay process here. --> You can suggest other ways if any.

In the above process, I was trying to generate 10000 events but it hardly giving me 10 events at the end (after taking longer time).
Can you please help ?

Thanks,
Subhasish

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
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Solved by:
SUBHASISH BEHERA
Solved:
2020-07-23
Last query:
2020-07-23
Last reply:
2020-07-23

Did you use cut to avoid singularities of the matrix-element?

Cheers,

Olivier

> On 23 Jul 2020, at 14:15, SUBHASISH BEHERA <email address hidden> wrote:
>
> New question #692022 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/692022
>
> Dear Olivier,
>
> I was trying to generate the following process :
> generate .. > .. , h > all all all all $all QED<=99
> It is a process with single Higgs production, which will further decay to 4-particles.
> The process would have 1380 diagrams.
>
> In fact I was trying to produce inclusive Higgs decay process here. --> You can suggest other ways if any.
>
> In the above process, I was trying to generate 10000 events but it hardly giving me 10 events at the end (after taking longer time).
> Can you please help ?
>
> Thanks,
> Subhasish
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Olivier,

 I have not used any cut till now.
I have not set cut_decay = True.
Will this work ?

Thanks,
Subhasish

You need to be carefull here, and i guess change your syntax.

The issue is likely that you have process like
h > b b~ g g
and
h > b b~ a a
(and likely many others).
which are not finite at LO without cuts.
So if you want to include those, you need to set cut_decay = True
and set a bunch of cuts to avoid such singularities. But in general you do not want to study such type of decay (and only include such radiation at Leading Log accuracy via the parton-shower)

Cheers,

Olivier

Dear Olivier,

Many thanks for your reply. I agree with you.

>You need to be carefull here, and i guess change your syntax.

Will the following suffice (for INCLUSIVE decay of Higgs boson):
define dd = w+ w- z ta- ta+ t t~ b b~
generate ... > ..., h > dd dd $dd QED <=99

and then send it to Parton-shower ?

Thanks,
Subhasish

No because an Higgs can not decay to two W/Z onshell
So you will not include that case.

> On 23 Jul 2020, at 15:50, SUBHASISH BEHERA <email address hidden> wrote:
>
> Question #692022 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/692022
>
> Status: Answered => Open
>
> SUBHASISH BEHERA is still having a problem:
> Dear Olivier,
>
> Many thanks for your reply. I agree with you.
>
>> You need to be carefull here, and i guess change your syntax.
>
> Will the following suffice (for INCLUSIVE decay of Higgs boson):
> define dd = w+ w- z ta- ta+ t t~ b b~
> generate ... > ..., h > dd dd $dd QED <=99
>
> and then send it to Parton-shower ?
>
> Thanks,
> Subhasish
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Olivier,
Thanks for your answer.

Thanks,
Subhasish