decay higgs boson in MadSpin using different model

The only mode of madspin working with loop_induced decay and the stupid one (set splinmode=none)
where you do not have any off-shell effect and no spin-correlation.

The algorithm is actually to generate one sample for the decay and glue those decay event with the production one
without trying to improve the precision of such prediction.

The only case where this mode is sensible is for the standard model Higgs.
Since this is a scalar they are no spin-correlation between production and decay
and since the width is super small, no observable are sensitive.

So as long as your modification does not lead to a blow up of the width of the Higgs, you should be fine.

Concerning changing the model between production and decay in this mode, they are no issue:
You have the syntax for it here: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/MadSpin#Fulllistofoptions

Cheers,

Olivier

> On 15 Nov 2023, at 22:10, user1905 <email address hidden> wrote:
>
> New question #708456 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/708456
>
> Hi Experts,
> I am trying to implement some new physics which induces changes in HVV couplings in MadGraph5. The process i am trying to look is higgs production via gluon fusion which is loop induced. Since my model does not handle loop process and on top of that since the new physics i am interested only comes into the decay of higgs, i was thinking if somehow i could use the new physics UFO model while decay in Madspin and usual loop_sm while generating higgs boson.
>
> Is this even possible?
>
> Thanks
>
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