MadGraph5_aMC@NLO

Distinguishing chiralities in MadGraph

Asked by mathieu.buchkremer@uclouvain.be

Dear MG team,

Considering a vector-like model, I would like to know if it is possible to distinguish clearly between quarks chiralities in a consistent simulation. Considering top pair production with tops decaying to Wq such that p p > t t~ > w+ w- q q :

Do you know if there would be any consistent way to isolate the 4 branches :
t t~ > w+ w- qL qL
t t~ > w+ w- qL qR
t t~ > w+ w- qR qL
t t~ > w+ w- qR qR

in MadGraph ?

The "t" could be here either the top or a vector-like quark top allowing for both L and R couplings to the SM quarks q. This
looks similar to helicity amplitudes, i.e. splitting the problem in irreducible pieces and recomposing them differently. Do you think this would be feasible, either at the model or the generator level ?

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi Matthieu,

We don't have anything "nice" (i.e fully automatic)
but you can look how to do this at the following link:
https://answers.launchpad.net/madgraph5/+faq/2243

If you are interested to make those modifications in a automated way, we can work on that together.
I know a couple of people who will be interested in such implementation.
(If you want, you can contact me on Skype: mattelaerolivier)

Cheers,

Olivier

On Jun 5, 2013, at 10:16 AM, <email address hidden> <email address hidden> wrote:

> New question #230236 on MadGraph5:
> https://answers.launchpad.net/madgraph5/+question/230236
>
> Dear MG team,
>
> Considering a vector-like model, I would like to know if it is possible to distinguish clearly between quarks chiralities in a consistent simulation. Considering top pair production with tops decaying to Wq such that p p > t t~ > w+ w- q q :
>
> Do you know if there would be any consistent way to isolate the 4 branches :
> t t~ > w+ w- qL qL
> t t~ > w+ w- qL qR
> t t~ > w+ w- qR qL
> t t~ > w+ w- qR qR
>
> in MadGraph ?
>
> The "t" could be here either the top or a vector-like quark top allowing for both L and R couplings to the SM quarks q. This
> looks similar to helicity amplitudes, i.e. splitting the problem in irreducible pieces and recomposing them differently. Do you think this would be feasible, either at the model or the generator level ?
>
> --
> You received this question notification because you are a member of
> MadTeam, which is an answer contact for MadGraph5.

Revision history for this message
mathieu.buchkremer@uclouvain.be (mathieu-buchkremer) said : 		#2

Thanks Olivier Mattelaer, that solved my question.