Absence of gg>ZZ in pp>ZZ[QCD] (mg5_aMC 2.3.3)

Dear Cyril,

The Loop-Induced contribution is at N^2LO contribution and not a NLO contribution.
So this is consistent to not include it when you do [QCD] on a process which has tree-level diagram.

Otherwise it is not possible to have those two computation simultaneously.
The method to perform the phase-space is very different and allow such combination will be time consuming and not worth the time.

Cheers,

Olivier

> On Mar 8, 2016, at 20:30, Cyril Becot <email address hidden> wrote:
>
> Question #288279 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/288279
>
> Description changed to:
> Dear mg5_aMC team,
>
> I have a small question regarding the syntax(s) for loop-induced processes and the processes that a NLO generation include
> I want to generate the process pp->ZZ->4l (continuum), including the loop-induced gg->ZZ part
>
> I first used the following command :
> generate p p > ZZ [QCD]
>
> However looking at the output diagrams, the box gg->ZZ seemed missing
> Now when I try to do
> generate p p > ZZ [noborn=QCD]
>
> I get the gg->ZZ box, but I lose the tree level quark-inititated
> diagrams
>
> Is there a syntax that allows to keep all the processes in one run ? And why the first one discard the box while it appears at NLO ?
> (This is not a really big deal as it's possible to generate the box and the rest separately. I'd just like to understand what's going on)
>
> Kind regards,
> Cyril
>
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