How to obtain information of election/pion parent particle?

Physics Processes, Models and Cross Sections
1

The problems encountered when simulating antiproton incidence on a silicon detector.
In the process involving photon production of positrons and electrons（conv）, as well as something decaying to produce pion mesons(Decay), the result doesn’t show any information about their parent particles. I can’t trace its whereabouts upward.

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Does anyone know what the reason for this is?

2

Hello,

this doesn’t look like straight from Geant4. Ask someone closer to the generation of the ROOT file you are reading.