gluinos and CKKW(L) merging with Pythia8

Asked by andlessa on 2019-06-03

Hi,

I have a question about the CKKW matching with Pythia8. I have a simple process: gluino pair production with up to one additional parton (the decays are done in Pythia).
I see that by default the ktdurham cut in run_card.dat also applies to the gluino final states:

1, 2, 3, 4, 5, 6, 21, ... 1000021,... = pdgs_for_merging_cut ! PDGs for two cuts above

Does this make sense? As far as I understand the cut should be used to regulate the soft emission of the light partons,
so I'm not sure why the gluino pdg is there.
Also I've noticed that including or not the gluino PDG has a significant impact on the cross-section/merged events.

Cheers,

-Andre

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Last query:
2019-06-03
Last reply:
2019-06-03

Hi,

To be honest, I do not know.
This setup (and how it works) was requested by S. Prestzel which is the expert in matching/merging.
Now, you also want to regulate the soft emission from those particles so it does make sense to me.
But I would suggest to contact Stefan for more details.

Cheers,

Olivier

> On 3 Jun 2019, at 17:17, andlessa <email address hidden> wrote:
>
> New question #681213 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/681213
>
> Hi,
>
> I have a question about the CKKW matching with Pythia8. I have a simple process: gluino pair production with up to one additional parton (the decays are done in Pythia).
> I see that by default the ktdurham cut in run_card.dat also applies to the gluino final states:
>
> 1, 2, 3, 4, 5, 6, 21, ... 1000021,... = pdgs_for_merging_cut ! PDGs for two cuts above
>
> Does this make sense? As far as I understand the cut should be used to regulate the soft emission of the light partons,
> so I'm not sure why the gluino pdg is there.
> Also I've noticed that including or not the gluino PDG has a significant impact on the cross-section/merged events.
>
> Cheers,
>
> -Andre
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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