external setup of branching ratios in BSM model

Dear Alexandra,

All the information about the model are pass via the param_card so in principle you never have to change anything to the central system.

Now if you use the decay chain syntax: generate p p > w+ w-, w+ > all, w- > all all
then you the information that are use are the coupling. i.e. the value of the branching ratio can only be set by an ad-hock (and coherent) value of the model parameter.
So typically, this actually to play with the Branching Ratio.

On the other hand in MadSpin, the Branching Ratio is used.
By default if the BR information is present in the file, then MadSpin will use the specified information.
If the information is missing for at least one particle then MadSpin will ask MadWidth to recompute the width/partial width/BR for all the the particle of the model (computation ask only for 2 body decay)
So here you can play and put unphysical value of the BR if you want to.

Cheers,

Olivier

On 26 Mar 2015, at 20:11, alexandra <email address hidden> wrote:

> New question #264182 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/264182
>
> Dear developers
>
> In context of experiment and look for BSM resonance we want to set by hand the branching ratios of a new resonance bypassing a complete model calculation.
>
> It would be possible to do it in a straightforward way giving a already constructed BSM model files,
> but without modify the Madgraph_aMC@NLO files (that for instance are uploaded in central system)?
>
> Could MadSpin help?
>
> thank you
> Alexandra
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thank you Olivier