LO bias and additional jets via "add process"

Asked by Hannes on 2017-11-17

Dear authors,

I am trying to implement a bias function that depends on the extra jets in events like
> p p > w+
> add process p p > w+ j
> add process p p > w+ j j

However, I do not know an easy way to actually access the kinematics of the extra jets because "nexternal" (as used in the example ptj_bias module) always corresponds to the number of particles of the lowest-multiplicity subprocess and I cannot loop over the additional jets.
I am probably missing something obvious, how would I access the momenta of the extra jets from within the bias module in such a case?

Cheers,
Hannes

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Hannes
Solved:
2017-11-20
Last query:
2017-11-20
Last reply:
2017-11-17

Hi Hannes,

This is a design flaw of such routine, this need to be rewritten if someone wants to have this working with more than one multiplicity.
I’m looking at it but this is more complex than anticipated.

Cheers,

Olivier

> On Nov 17, 2017, at 17:17, Hannes <email address hidden> wrote:
>
> New question #660866 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/660866
>
> Dear authors,
>
> I am trying to implement a bias function that depends on the extra jets in events like
>> p p > w+
>> add process p p > w+ j
>> add process p p > w+ j j
>
> However, I do not know an easy way to actually access the kinematics of the extra jets because "nexternal" (as used in the example ptj_bias module) always corresponds to the number of particles of the lowest-multiplicity subprocess and I cannot loop over the additional jets.
> I am probably missing something obvious, how would I access the momenta of the extra jets from within the bias module in such a case?
>
> Cheers,
> Hannes
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hannes (hannes3) said : #2

Hi Olivier,

thanks for the quick reply and for looking into this.
It is good to know that it is indeed non-trivial and I have not been missing something obvious.
I don't know whether this feature is urgently needed, but being able to bias e.g. based on HT might be useful.

Cheers,
Hannes