e+ e- problem to generate events

Asked by Jilberto Zamora-Saa on 2019-05-14

Dear All

I'm trying to generate events for the process:

e+ e- > ta+ ta- , ta+ > j j vt~

The beam energy is 4 and 7 GeV respectively. When I simulated 10000 events the output file (lhe) contains only 3 events (entries). I'm using Madgraph V_6_3_2

Any help is welcome

cheers,
Jilberto

Question information

Language:
English Edit question
Status:
Answered
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MadGraph5_aMC@NLO Edit question
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Last query:
2019-05-14
Last reply:
2019-05-15

Hi,

This is related to a numerical issue related to the tau width.
Starting with 2.6.4, we have implemented a method to avoid those numerical issue (and which also fasten the code quite a lot) See: https://answers.launchpad.net/mg5amcnlo/+faq/3053 for more information

In the latest version, I have run the following script:
> import model sm-full
> generate e+ e- > ta+ ta- , ta+ > j j vt~
> output
> launch
> set ebeam1 4
> set ebeam2 7
> set no_parton_cut

and get result directly. (less than 30s).

> Cross-section : 437.9 +- 1.092 pb
> Nb of events : 10000

Cheers,

Olivier

> On 14 May 2019, at 23:47, Jilberto Zamora-Saa <email address hidden> wrote:
>
> New question #680819 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/680819
>
> Dear All
>
> I'm trying to generate events for the process:
>
> e+ e- > ta+ ta- , ta+ > j j vt~
>
> The beam energy is 4 and 7 GeV respectively. When I simulated 10000 events the output file (lhe) contains only 3 events (entries). I'm using Madgraph V_6_3_2
>
> Any help is welcome
>
> cheers,
> Jilberto
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Jilberto Zamora-Saa (sirjazs) said : #2

Dear Olivier, thank for your answer!!

However, now I'm having a new problem:

My events are generated exactly as you aforementioned (in the lhe file).

Now, I'm triying to run Pythia and Delphes, both ran perfectly, however, when I go to the delhes output file (root file) is empty. I think that there is a problem with the kinematical cut in the default delfes card. Could you help me with this issue, please.

Thank in advance,
Jilberto

Hi,

Sorry but I have no clue on how the Delphes setup is done in order to define another detector.
I will not be able to help you on that.

Cheers,

Olivier

Jilberto Zamora-Saa (sirjazs) said : #4

Dear Oliver,

Thanks,
Jilberto

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