electron proton collision via MadGraph and Pythia6

Hi,

Those are question for pythia6/pythia8. Pythia6 being not supported anymore since ~10 years and even not compatible with modern compiler -- I can not compile it on my laptop for example--. You will have to use Pythia8 (or Herwig7)

Cheers,

Olivier

> On 25 Jul 2021, at 08:20, Reza Jafari <email address hidden> wrote:
>
> New question #698139 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/698139
>
> Dear Experts,
>
> I am trying to generate data for the process of e- p > vl j t~ with p = p b b~.
> In the MadGraph level everything is fine. But when I switch Pythia6 on, there is not any event in the output file.
> Is there any solution for this problem?
>
> Note: As pythia8 is not compatible for ep collision, I use pythia6 and I receive these messages:
> INFO: Pythia6 needs a specific normalisation of the events. We will change it accordingly.
> INFO: modify parameter event_norm of the run_card.dat to sum
>
> In general, is there any new update in MadGraph shell to perform showering and hadronization for ep collisions?
>
> Thanks in advance.
>
> Best Regards,
> Reza
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Olivier,

Thanks for your prompt answer.
I am using pethia8 in all cases. But I've heard pythia8 is not compatible for ep collision.

Cheers,

Reza

I'm not aware of that but I'm not an expert on that kind of physics (especially for the parton-shower part)

Cheers,

Olivier

> On 25 Jul 2021, at 09:25, Reza Jafari <email address hidden> wrote:
>
> Question #698139 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/698139
>
> Reza Jafari posted a new comment:
> Dear Olivier,
>
> Thanks for your prompt answer.
> I am using pethia8 in all cases. But I've heard pythia8 is not compatible for ep collision.
>
> Cheers,
>
> Reza
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Reza,
I have same question when using MadGraph + pythia8 +Delphes to generate events at ep collider.

How did you solve it？

Best
Yao-Bei

Hi lyb,

To solve this issue, I used the default pythia8 card finally and did the following commands:

1- Using "p e" instead of "e p" in MadGraph5 to generate events.
2- Use "weighted<=99" option after my command for simulating events, i.e. "generate p e- > vl j t~ weighted<=99". It helps to remain some events in the output instead of an empty file, and you can manage your simulation by using multi_run command in MadGraph5 to generate more events to have a suitable sample of events after passing in pythia8.

By the way, I had communicated with Pythia8 authors, but no solution was given finally. However, they believe pythia8 is compatible for all ep collision events.

Best,
Reza