MadGraph5_aMC@NLO

Treating b-quarks identically to d and s quarks

Asked by Jack Medley

Hello,
I am trying to export some standalone (cpp) matrix elements from MadGraph 5.
At the moment if I generate, for example, p p > e+ e- p p, the subproccesses involving b quarks are treated differently to the d and s quarks (presumably because the b is modelled with a non-zero mass?)
Is it possible to have MadGraph treat the d, s and b on an identical footing when grouping subprocceses?
Cheers,
Jack

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi Jack,

You just need to set the mass to zero at the model level.
If this is SM process
you can do that via the command
import model sm-no_b_mass
instead of the import model sm line.

Cheers,

Olivier

On Mar 31, 2014, at 2:21 PM, Jack Medley <email address hidden> wrote:

> New question #246290 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/246290
>
> Hello,
> I am trying to export some standalone (cpp) matrix elements from MadGraph 5.
> At the moment if I generate, for example, p p > e+ e- p p, the subproccesses involving b quarks are treated differently to the d and s quarks (presumably because the b is modelled with a non-zero mass?)
> Is it possible to have MadGraph treat the d, s and b on an identical footing when grouping subprocceses?
> Cheers,
> Jack
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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Jack Medley (jack-medley) said : 		#2

Thanks, thats one the trick.
Jack