Trk::TrackTruthCollection_p3::Entry Node1 Trk::TrackTruthCollection _p3::Entry + index + probability Node2 HepMcParticleLink_p3 # m_mcEvtIndex # m_evtColl + HepMcParticleLink_p3() + HepMcParticleLink_p3() Node2->Node1 +particle Node3 long Node3->Node2 #m_id