what IDEN to use

Hi,

The reason of the 72 is
3 ! color factor for particle 1
3 ! color factor for particle 2
2 ! number of helicity of particle 1
2 ! number of helicity of particle 2
2 ! symmetry factor due to the presence of two W in the final state.

This number can sometimes be bigger for some of the matrix-element since the symmetry factor depend of the identity of the particle
matrix1.f and matrix2.f have a different number for example.

So in practise, you do not have to change this number for two longitudinal w

Cheers,

Olivier

On Aug 28, 2014, at 3:07 PM, Andrew Levin <email address hidden> wrote:

> New question #253741 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/253741
>
> Hi,
>
> I am following the instructions here about how to generate longitudinal final state particles
>
> https://answers.launchpad.net/mg5amcnlo/+faq/2243
>
> but I am not really sure what to change IDEN factor to for the process I am interested in
>
> p p > w- w- j j
>
> It starts as 72 (I guess it is 3! * 3! *2 ?) and I want to make the two ws longitudinally polarized.
>
> Can someone help me with this?
>
> Thanks.
>
> Andrew
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.