the difference between "generate p p > n2 x1-, (n2 > z n1, x1- > w- n1)" and "generate p p > n2 x1-"

Hi,

MadGraph does not use the BR information at all for such kind of computation.
(which actually allows you to set cut in the final states).

So a crucial parameter for us is the total width. If that parameter is not set to the correct value, the two cross-section will not match.

> "generate p p > n2 x1-, (n2 > z n1, x1- > w- n1)" and "generate p p > n2 x1-" in MadGraph5?

Obviously the main differenc is your final state.
Note that your fist syntax is actually wrong
I guess you want to say
> generate p p > n2 x1-, n2 > z n1, x1- > w- n1

Cheers,

Olivier

> On 16 Jan 2020, at 15:08, Di Zhang <email address hidden> wrote:
>
> New question #688039 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/688039
>
> Dear authors,
>
> If Br(n2 > z n1)=1 and Br(x1- > w- n1) in the param_card.dat, what is the difference between "generate p p > n2 x1-, (n2 > z n1, x1- > w- n1)" and "generate p p > n2 x1-" in MadGraph5?
>
> I am looking forward to your reply and thank you in advance.
>
> Your sincerely,
> Di Zhang.
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,

Thank you for your reply soon!

My progress is p p > n2 x1-, n2 > z n1, x1- > w- n1, and I swiched the Pythia8 on. How to set the Br(n2 > z n1)=1 and Br(x1- > w- n1)=1 in MadGraph5?

You said 'the two cross-section will not match' and I am wonder what the two cross section are.

Your sincerely,

Di Zhang.

Thanks Olivier Mattelaer, that solved my question.