CKKW-L merging in mg5+py8

For the pythia8 parameter for CKKW-L, the best is to ask Pythia8 author.
We have more experience in MLM than with CKKW-L (where all the tricks are actually done in Pythia8 and where they are nothing special on our side).

Note that
> decay sd3 > b h01 n1
> decay sd3~ > b~ h01 n1

Can not be done in full precision in MadSpin. I guess that you are using spinmode=onshell for this.
This mode can indeed be quite slow.

Cheers,

Olivier

> On 2 Jul 2020, at 20:01, Jack Y. Araz <email address hidden> wrote:
>
> New question #691647 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/691647
>
> Dear Olivier
>
> I'm following ATLAS-SUSY-2018-031 analysis to generate sbottom production using MSSM-SLHA2 model with additional 2 jets and modified the given param cards in HEPData to use it in Mg5. The sample is generated in following way
>
> generate p p > sd3 sd3~ @1
> add process p p > sd3 sd3~ j @2
> add process p p > sd3 sd3~ j j @3
>
> and I decayed it via madspin
>
> decay sd3 > b h01 n1
> decay sd3~ > b~ h01 n1
>
> (I know it ruins the physics but I'm letting Pythia to decay higgs. When I define h01 > all all, w (+ and -) > all all, z> all all it cant decay 100 events in 20h)
>
> To activate CKKW-L merging I turned off MLM ( 0 = ickkw) and set 30.0 = ktdurham. Also in py8 card
>
> Merging:TMS = 275.0
> Merging:Process = pp>sd3,sd3~
> Merging:nJetMax = 2
> Merging:nJetMax = 2
> Merging:doMGMerging = on
> Tune:pp = 21
>
> However, I realised that Pythia asks me the following;
>
> Use default process pp -> e+ve + jets? (0:no / 1:yes):
>
> in the log file but this does not appear on the terminal so I killed the process and tried to run it using run_shower.sh script and realised that py8 keeps asking me all the questions that are entered in the command card for every single event. Am I missing something during initialization, is there a way to automatize this?
>
> MG5 v 2.7.3
>
> Thanks
> Best regards
> Jack
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks Olivier, I'll ask it to py8 authors.

>Can not be done in full precision in MadSpin. I guess that you are using spinmode=onshell for this.
This mode can indeed be quite slow.

I even tried it with spinmode=none but it was still slow. I also tried to define the full decay chain during generation but then it couldn't finish creating the output folder. Is there any trick that I can use to define the entire decay chain? Its a long one sd3 > b n2, n2 > h01 n1, h01 > everything

Thanks

Best regards
Jack

This question was expired because it remained in the 'Open' state without activity for the last 15 days.