HepMcTupleWriterTool::HepMcParticles Node1 HepMcTupleWriterTool ::HepMcParticles + m_nParticles Node2 std::array< double, s_nMax > + elements Node2->Node1 +m_px +m_py +m_pz +m_ene +m_m Node3 std::array< int, s _nMax > + elements Node3->Node1 +m_status +m_pdgId +m_barcode