Off-shell decay for a particular process

Dear kai,

I do not know the model, so difficult to asses for sure the syntax corresponding to what you are looking for.
I would go for
> g g > H2 > H1 H1 ve ve, H1 > b b~

you can also try
> g g > H2 ~n1 > H1 H1 ve ve, H1 > b b~

which is closer to your original syntax and might have less diagram.
Obviously if both syntax do not have the same number of diagram, you need to justify why you can remove those diagrams and neglect the interference between those diagrams
(which is not trivial when particle are off-shell)

Cheers,

Olivier

> On Aug 15, 2016, at 10:52, kai <email address hidden> wrote:
>
> New question #344754 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/344754
>
> Dear MadGraph Team,
>
> I have the following vertex in my model:
>
> g g > H2 > ~n1 ~n1 , ( ~n1 > H1 ve , H1 > b b~ )
>
> where H2 is a new higgs and H1 is SM-higgs, ~n1 represents heavy neutrino.
> The parameter space I am interested in includes where mass of H2 < 2*mass of ~n1.Besides, the mass spectra of H2 will be quite broad. So it is necessary to generate events allowing off-shell H2 decay and I need to allow ~n1 (one or both) to be off-shell.
>
> But when I generate : g g > H2 > ~n1 ~n1 , ( ~n1 > H1 ve , ( H1 > b b~ ) ) following similar questions
>
> However it looks that both ~n1 are forced to be on-shell and give a wrong mass spectra for H2 when I sum up two 4-vectors of ~n1
>
> Could you please figure out how to input the correct syntax?
>
> Thanks,
> Kai
>
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