TrackTruthDecoratorAlg.h

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef TRACK_TRUTH_DECORATOR_ALG_HH
#define TRACK_TRUTH_DECORATOR_ALG_HH
 
#include "AthenaBaseComps/AthReentrantAlgorithm.h"
#include "GaudiKernel/ToolHandle.h"
#include "AthContainers/AuxElement.h"
#include "StoreGate/WriteDecorHandleKey.h"
#include "StoreGate/ReadDecorHandleKey.h"
 
#include "xAODTruth/TruthParticleContainerFwd.h"
#include "xAODTruth/TruthEventContainer.h"
#include "xAODMuon/MuonContainer.h"
#include "InDetTrackSystematicsTools/InDetTrackTruthOriginTool.h"
#include "TruthClassification/TruthClassificationTool.h"
 
 
namespace FlavorTagDiscriminants {
 
  class TrackTruthDecoratorAlg: public AthReentrantAlgorithm {
  public:
    TrackTruthDecoratorAlg(const std::string& name,
                          ISvcLocator* pSvcLocator );
 
    virtual StatusCode initialize() override;
    virtual StatusCode execute(const EventContext& ) const override;
 
  private:
    // Input Containers
    SG::ReadHandleKey< xAOD::TrackParticleContainer > m_TrackContainerKey {
      this, "trackContainer", "InDetTrackParticles",
        "Key for the input track collection"};
    SG::ReadHandleKey< xAOD::MuonContainer > m_MuonContainerKey {
      this, "muonContainer", "Muons",
        "Key for the input muon collection"};
    SG::ReadHandleKey< xAOD::TruthParticleContainer > m_truthParticleContainerKey {
      this, "truthParticleContainer", "TruthParticles",
      "Key for the input truth particle container"};
 
    // Accessors for truth particles
    using RDHK = SG::ReadDecorHandleKey< xAOD::TruthParticleContainer >;
    RDHK m_acc_type_label {
      this, "acc_ftagTruthTypeLabel", m_truthParticleContainerKey, "ftagTruthTypeLabel",
        "Accessor for the truth type label of the truth particle"};
    RDHK m_acc_source_label {
      this, "acc_ftagTruthSourceLabel", m_truthParticleContainerKey, "ftagTruthSourceLabel",
        "Accessor for the truth label for the source of secondary particles"};
    RDHK m_acc_vertex_index {
      this, "acc_ftagTruthVertexIndex", m_truthParticleContainerKey, "ftagTruthVertexIndex",
        "Accessor for the vertex index of the truth particle"};
    RDHK m_acc_parent_uniqueID {
      this, "acc_ftagTruthParentBarcode", m_truthParticleContainerKey, "ftagTruthParentBarcode",
        "Accessor for the uniqueID of the parent of linked truth particle"};
 
    // Decorators for tracks
    using WDHK = SG::WriteDecorHandleKey< xAOD::TrackParticleContainer >;
    WDHK m_dec_origin_label {
      this, "dec_ftagTruthOriginLabel", m_TrackContainerKey, "ftagTruthOriginLabel",
        "Exclusive origin label of the track"};
    WDHK m_dec_type_label {
      this, "dec_ftagTruthTypeLabel", m_TrackContainerKey, "ftagTruthTypeLabel",
        "Exclusive truth type label of the track"};
    WDHK m_dec_source_label {
      this, "dec_ftagTruthSourceLabel", m_TrackContainerKey, "ftagTruthSourceLabel",
        "Exclusive truth label for the source of secondary tracks"};
    WDHK m_dec_vertex_index {
      this, "dec_ftagTruthVertexIndex", m_TrackContainerKey, "ftagTruthVertexIndex",
        "ftagTruth vertex index of the track"};
    WDHK m_dec_uniqueID {
      this, "dec_ftagTruthBarcode", m_TrackContainerKey, "ftagTruthBarcode",
        "UniqueID of linked truth particle"};
    WDHK m_dec_parent_uniqueID {
      this, "dec_ftagTruthParentBarcode", m_TrackContainerKey, "ftagTruthParentBarcode",
        "UniqueID of parent of linked truth particle"};
    WDHK m_dec_muon_origin_label {
      this, "dec_ftagTruthMuonOriginLabel", m_TrackContainerKey, "ftagTruthMuonOriginLabel",
        "Exclusive origin label of the muon"};
 
 
    // Truth origin tool
    ToolHandle<InDet::InDetTrackTruthOriginTool> m_trackTruthOriginTool {
      this, "trackTruthOriginTool", "InDet::InDetTrackTruthOriginTool", 
        "track truth origin tool"};
    // Truth Lepton Origin tool (https://gitlab.cern.ch/atlas/athena/-/tree/main/PhysicsAnalysis/AnalysisCommon/TruthClassification)
    ToolHandle<CP::IClassificationTool> m_truthLeptonTool{
      this, "truthLeptonTool", "",
        "Lepton truth classification tool"};
 
    // Defining a map for proper muon origin labels 
    std::unordered_map<Truth::Type,unsigned int> m_muTruthMap = {
      {Truth::Type::Unknown, 0}, //Fake(Uknown) muon
      {Truth::Type::KnownUnknown, 1}, //KnownUknown muon
      {Truth::Type::PromptMuon, 2}, //Prompt muon
      {Truth::Type::BHadronDecay, 3}, //From B muon
      // FromBC and FromC decay label are handled in the implementation since FromBC is not directly available for TruthClassificationTool
      // FromBC and FromC decay label are handled in the implementation since FromBC is not directly available for TruthClassificationTool 
      {Truth::Type::LightFlavorDecay, 6}, //From light muon
      {Truth::Type::TauDecay, 7}, //From tau muon
      {Truth::Type::TauDecayLike, 8}, //4-like muons
      {Truth::Type::BHadronDecayLike, 8}, //4-like muons
      {Truth::Type::CHadronDecayLike, 8}, //4-like muons
      {Truth::Type::NonMuonlike, 8}, //Non-muons like muons
      // There are also cases where the muon has the truth particle associated to the ID track that is not a muon. Those muons are labelled as 9 (NotInnerDetector muons)
    };
 
    // ATLASRECTS-8290: this is for backward compatability, remove eventually
    Gaudi::Property<bool> m_use_barcode {
      this, "useBarcode", false, "use barcode rather than UID"
    };
    SG::ConstAccessor<int> m_uid{"uid"};
 
  };
}
 
#endif