pion decay in MadGraph

Asked by Y Du on 2018-04-21

Hi experts,

I have been using MadGraph for a while, but recently I'm switching a little bit and want to study pions. Immediately I run into a problem--Let's say I want to study the decay width of the positive charged pion, how shall I do that?

If I use p p > u d~, then how can I even reconstruct the invariant mass of the pion since MadGraph can not tell us any information about light quarks since we only have b tag and c tag.

This question may be too silly, but thanks in advance.

Best,
Yong

Question information

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MadGraph5_aMC@NLO Edit question
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Last query:
2018-04-21
Last reply:
2018-04-21

Hi,

 MG5aMC only handle perturbative theory.
So if you want to do pion physics within our framework, you need to use a perturbative model.
For the computation of the width of the pion, you probably need an effective theory (with form factor) in order to handle correctly the pion.

I'm not aware of anyone who have implemented such model in a UFO format. But FeynRules is certainly able
to generate such type of UFO model if someone provide to him the associate Lagrangian.

> If I use p p > u d~, then how can I even reconstruct the invariant mass of the pion since MadGraph can not tell us any information about light quarks since we only have b tag and c tag.

Following my comment above, I do not think that it makes that much sense to mix the two pictures for the quark.
Actually in the past, we had a module (in MG4) called MadOnia who was able to handle quarkonium production. This project is not supported anymore since 2009 (and the main author left physics)
But another project called HelacOnia does exists (actually the main author is now an author of MG5aMC)
I have no clue if such tools can handle pion production but it might be interesting to check.

Cheers,

Olivier

> On 21 Apr 2018, at 16:27, Y Du <email address hidden> wrote:
>
> New question #668155 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/668155
>
> Hi experts,
>
> I have been using MadGraph for a while, but recently I'm switching a little bit and want to study pions. Immediately I run into a problem--Let's say I want to study the decay width of the positive charged pion, how shall I do that?
>
> If I use p p > u d~, then how can I even reconstruct the invariant mass of the pion since MadGraph can not tell us any information about light quarks since we only have b tag and c tag.
>
> This question may be too silly, but thanks in advance.
>
> Best,
> Yong
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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