production of di-hh and decay channels

Hi,

How to do such kind of physics is actually explained in arXiv:1507.00020

You need to use MadSpin.
and put in the madspin_card the following three lines:
set spinmode=none
decay h > b b~
decay h > z z > l+ l- l+ l-

The command
(h>zz, z>l- l+ , z>l-l+) does not make sense since it request both Z to be onshell.
Which will bias your generation.

Cheers,

Olivier

Hi, thank you for your reply

here is what I did:
I entered the command: generate p p > h h [QCD]
then, I entered in madspin what you have told me:
                     -----------------------------------
#Some options (uncomment to apply)
# set spinmode=none
# set seed 1
# set Nevents_for_max_weigth 75 # number of events for the estimate of the
max. weight
# set BW_cut 15 # cut on how far the particle can be
off-shell
# set spinmode onshell # Use one of the madspin special mode
 set max_weight_ps_point 400 # number of PS to estimate the maximum for
each event

# specify the decay for the final state particles
decay h > b b~
decay h > z z > l+ l- l+ l-
# running the actual code
launch

 ----------------------------------

However, I got an error which says :
Command "generate_events run_02" interrupted with error:
NoDiagramException : No amplitudes generated from process Process:
g/u/c/d/s/u~/c~/d~/s~ g/u/c/d/s/u~/c~/d~/s~ > h h WEIGHTED=8 @1. Please
enter a valid process

So, what was the problem?

THANK YOU

Le jeu. 14 févr. 2019 à 15:31, Olivier Mattelaer <
<email address hidden>> a écrit :

> Your question #678557 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/678557
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> How to do such kind of physics is actually explained in arXiv:1507.00020
>
> You need to use MadSpin.
> and put in the madspin_card the following three lines:
> set spinmode=none
> decay h > b b~
> decay h > z z > l+ l- l+ l-
>
> The command
> (h>zz, z>l- l+ , z>l-l+) does not make sense since it request both Z to be
> onshell.
> Which will bias your generation.
>
>
> Cheers,
>
> Olivier
>
> --
> 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/678557/+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/678557
>
> You received this question notification because you asked the question.
>

Why the line
set spinmode=none
is commented?

Cheers,

Olivier

Hii,

Oh yeah, now it works thank you a lot.

I have just two extra questions :
1- having this done, the cross section computed is it for the whole needed
process i.e "pp> hh> b b~ zz(4l)" or just for pp > hh ( I know it might be
a silly question, I'm new in madgraph) ??
2- Is it possible to generate full Feynman diagrams where both the final
state (bb~ zz(4l)) and di-hh production modes appear?
3-would it be wrong if I do 'generate pp > bb~zz' (and then I make the
same changes in madspin_card as I did before) instead of the first case
(pp>hh[qcd])?

And again thank you so much

Le jeu. 14 févr. 2019 à 17:27, Olivier Mattelaer <
<email address hidden>> a écrit :

> Your question #678557 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/678557
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Why the line
> set spinmode=none
> is commented?
>
> Cheers,
>
> Olivier
>
> --
> 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/678557/+confirm?answer_id=2
>
> 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/678557
>
> You received this question notification because you asked the question.
>

Hi,

> 1- having this done, the cross section computed is it for the whole needed
> process i.e "pp> hh> b b~ zz(4l)" or just for pp > hh ( I know it might be
> a silly question, I'm new in madgraph) ??

If you look at crossx.html you should see both number reported.

> 2- Is it possible to generate full Feynman diagrams where both the final
> state (bb~ zz(4l)) and di-hh production modes appear?

No

> 3-would it be wrong if I do 'generate pp > bb~zz' (and then I make the
> same changes in madspin_card as I did before) instead of the first case
> (pp>hh[qcd])?

You should check yourself. Generate the diagram and check if this is want you want.
Two remark though
1) If you do something like
> pp > bb~zz
this force both Z to be onshell. (i.e. this might not be what you want)
2) madspin=none is a quite unprecise mode. That mode is perfect for the Higgs but quite Bad for W/Z decay (since they have quite large width and that they are spin 1) . So I would not advise to use madspin in that case.

Cheers,

Olivier

> On 14 Feb 2019, at 18:07, TAIL Saad <email address hidden> wrote:
>
> Question #678557 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/678557
>
> Status: Answered => Open
>
> TAIL Saad is still having a problem:
> Hii,
>
> Oh yeah, now it works thank you a lot.
>
> I have just two extra questions :
> 1- having this done, the cross section computed is it for the whole needed
> process i.e "pp> hh> b b~ zz(4l)" or just for pp > hh ( I know it might be
> a silly question, I'm new in madgraph) ??
> 2- Is it possible to generate full Feynman diagrams where both the final
> state (bb~ zz(4l)) and di-hh production modes appear?
> 3-would it be wrong if I do 'generate pp > bb~zz' (and then I make the
> same changes in madspin_card as I did before) instead of the first case
> (pp>hh[qcd])?
>
> And again thank you so much
>
>
> Le jeu. 14 févr. 2019 à 17:27, Olivier Mattelaer <
> <email address hidden>> a écrit :
>
>> Your question #678557 on MadGraph5_aMC@NLO changed:
>> https://answers.launchpad.net/mg5amcnlo/+question/678557
>>
>> Status: Open => Answered
>>
>> Olivier Mattelaer proposed the following answer:
>> Why the line
>> set spinmode=none
>> is commented?
>>
>> Cheers,
>>
>> Olivier
>>
>> --
>> 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/678557/+confirm?answer_id=2
>>
>> 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/678557
>>
>> 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.