No initial state particles

Hi Sebastian,

The problem is related to the way pythia6 works: it uses a status code of 3 for all the particles associated with the hard process in MadGraph. As a consequence, those particles are considered as intermediate by madanalysis 5 (since they have the statuscode 3). In order to access them, you may need to know that:
 - the particles 0 and 1 are the colliding protons;
 - the particles 2 an 3 are the colliding partons.
By modifying the code generated by madanalysis 5, you should then be able to get the information you want.

I hope this helps.

Cheers,

Benjamin

PS: the launchpad janitor is a robot… it is useless to ask it anything :)

On 08 Oct 2015, at 19:08 , Sebastian Bruggisser <email address hidden> wrote:

> New question #272216 on MadAnalysis 5:
> https://answers.launchpad.net/madanalysis5/+question/272216
>
> Dear all,
>
> I am running an analysis in MA5 expert mode of some .hep files. The files are a result of a MadGraph/Pythia simulation. For my analysis I need access to initial state particles. However there don't seem to be any visible in MA5. Here is an example code I am using:
>
> if (event.mc()!=0)
> {
> for (unsigned int i=0;i<event.mc()->particles().size();i++)
> {
> const MCParticleFormat& part = event.mc()->particles()[i];
> if (PHYSICS->Id->IsInitialState(part))
> {
> cout << "an initial state particle" << endl;
> }
> }
> }
>
> which doesn't display anything (if I am only using final state particles of the same data set, everything is fine). Also I tried using
>
> part.statuscode()
>
> where I see that all particles are either final state particles (statuscode = 1) or intermediate states (statuscode 2 and 3).
>
> Is there a way to recover the initial state particles?
>
> Thanks in advance,
> Sebastian
>
>
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