small events run over first 2 generation quarks

Hi,

I would suggest to try to add the following line before the generate one:
set group_subprocesses False

This should forbid the use of some optimization of the code which might be the reason of your problem.

Cheers,

Olivier
On Jun 18, 2014, at 10:56 PM, Renjie Wang <email address hidden> wrote:

> New question #250420 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/250420
>
> Dear experts,
>
> I made a model coupling the first 2 generation quarks with a Dirac fermion (self-made),
> the over-all coupling of effective interaction is quark mass dependent. An interesting I found,
>
> when I do:
> generate c c~ > z x x~, z > ll+ ll-
> add process s s~ > z x x~, z > ll+ ll-
> or
> generate u u~ > z x x~, z > ll+ ll-
> add process d d~ > z x x~, z > ll+ ll-
>
> separately, it runs okay, give out the right event numbers as I requested, but when I mix the 1st & 2nd generation quarks:
> generate c c~ > z x x~, z > ll+ ll-
> add process d d~ > z x x~, z > ll+ ll-
> or
> generate p p > z x x~, z > ll+ ll-
>
> the simulation gets very very slow, and finally just give me 5 events from 1000 events I request,
>
> what's wrong with this? It looks like sensitive with quark mass, how can I solve this problem.
>
>
> Thanks ahead;
> Ren-Jie
>
> --
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> contact for MadGraph5_aMC@NLO.

Hi Olivier,

Awesome, the magic line solved my problem.

Thanks a lot;
Ren-Jie