MadSpin bridge mode with complicated process

The real way to go is to split the generation otherwise this sounds very complex.
In principle you can use the syntax
change cross_section {0: cross_section_0, 1: cross_section_1.}
but when quickly looking, I'm not sure that the banner will be correctly set in that case.

Cheers,

Olivier

> On 26 May 2022, at 17:11, Manu <email address hidden> wrote:
>
> New question #701971 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/701971
>
> Dear experts,
>
> I am generating a complicated process (with many 'add process') and trying to decay it with MadSpin in 'spinmode none' since I need three-body decays. MadSpin crashes with "InvalidCmd : The bridge mode of MadSpin does not support event files where events do not *all* share the same set of final state particles to be decayed. One workaround is to force the final cross-section manually."
>
> In this post https://answers.launchpad.net/mg5amcnlo/+question/697849, comment #3, you mention the workaround to have MadSpin not calculate the cross section but specify that myself. What is the command to turn off the cross section calculation?
>
> Best,
> Manuel
>
> --
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Thanks for your reply. Where do I have to put the change cross_section command? I get "command 'change' not recognized" when putting the line in the madspin_card or the steering script.

If at all possible I would like to avoid splitting the event generation since I have up to O(100) processes.

Just so I understand the potential issue: would that only affect the banner but the event file would be fine? I'm planning to feed the events into a recasting tool afterwards, so I could calculate the production cross section separately; I'm doing all possible decays anyway.

Best,
Manuel

Thanks Olivier Mattelaer, that solved my question.