Cheking decay to 3 particle

Hello Najimuddin,

Did you make sure to use a model where the muon is massive? By default, it has zero mass, and hence zero decay width. To get massive muon, import either sm-full or sm-lepton_masses. Note however that the muon width is too small to use a decayed muon as s-channel propagator in any scattering process. Tau is ok though.

All the best,
Johan

Hello Johan,
               Acording to your answer I set the mass of muon in
param_car.dat for electron and muon.even I set the mass of muon 1.777 Gev
but still I get zero answer.Thank you for your reply .

On Wed, Dec 5, 2012 at 10:15 AM, Johan Alwall <
<email address hidden>> wrote:

> Your question #215996 on MadGraph5 changed:
> https://answers.launchpad.net/madgraph5/+question/215996
>
> Status: Open => Answered
>
> Johan Alwall proposed the following answer:
> Hello Najimuddin,
>
> Did you make sure to use a model where the muon is massive? By default,
> it has zero mass, and hence zero decay width. To get massive muon,
> import either sm-full or sm-lepton_masses. Note however that the muon
> width is too small to use a decayed muon as s-channel propagator in any
> scattering process. Tau is ok though.
>
> All the best,
> Johan
>
> --
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>
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--
From
Najimuddin Khan
Research scholar
IIT Indore,
Khandwa Road,
Madhya Pradesh,
India-452017

Are you sure? When I do
import model sm-lepton_masses
generate mu- > e- ve~ vm
output
launch
I get the decay width 3.001e-19 ± 2.8e-21 GeV, which seems perfectly correct to me.

All the best,
Johan