Rec::TrackParticleTruthCollection_p1::Entry Node1 Rec::TrackParticleTruthCollection _p1::Entry + index + probability Node2 HepMcParticleLink_p1 # m_mcEvtIndex + HepMcParticleLink_p1() + HepMcParticleLink_p1() Node2->Node1 +particle Node3 long Node3->Node2 #m_barcode