KfpV0FinderCutter.h

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/* Copyright (C) 2025 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Sergei Zharko [committer] */

 
#ifndef KfpV0FinderCutter_h
#define KfpV0FinderCutter_h 0
 
#include "CbmYaml.h"
#include "algo/kfp/KfpV0FinderDefs.h"
 
#include <array>
#include <string>
 
class KFParticleFinder;
 
namespace cbm::algo::kfp
{
  template<EV0Type V0Type>
  class V0FinderCutter {
   public:
    template<typename T>
    using Range_t = std::array<T, 2>;  
 
    //* Different structures to store cut values

    struct TrackPidCuts {
      ETrackPid pid{ETrackPid::Undef};  
      Range_t<double> beta{{0., 1.}};   
 
      CBM_YAML_PROPERTIES(
        yaml::Property(&TrackPidCuts::pid, "pid", "Particle identifier"),
        yaml::Property(&TrackPidCuts::beta, "beta", "Speed [c]", YAML::Flow));
    };

    // FIXME: account for different particles (pi-, pi+, proton, anti-proton, .....)
    //        provided a vector/map to access the properties of each particle
    struct TrackCuts {
      std::vector<TrackPidCuts> pidCuts;
 
      CBM_YAML_PROPERTIES(yaml::Property(&TrackCuts::pidCuts, "pidCuts", "Track properties vs. PID", YAML::Flow));
    };

    struct KfpFinderCuts {
      float minDecayLength;  
      float minDecayLDL;     
      float maxChi2NdfPrim;  
      float maxChi2NdfGeo;   
 
      CBM_YAML_PROPERTIES(
        yaml::Property(&KfpFinderCuts::minDecayLength, "minDecayLength", "Min. decay length of particles [cm]"),
        yaml::Property(&KfpFinderCuts::minDecayLDL, "minDecayLDL", "Min. length to decay length error ratio"),
        yaml::Property(&KfpFinderCuts::maxChi2NdfPrim, "maxChi2NdfPrim", "Max. chi2/NDF for primary particles"),
        yaml::Property(&KfpFinderCuts::maxChi2NdfGeo, "maxChi2NdfGeo", "Max. chi2/NDF for V0 candidates"));
    };

    struct DaughterCuts {
      Range_t<double> dcaRelToOrigin;  
      Range_t<double> beta;            
 
      CBM_YAML_PROPERTIES(
        yaml::Property(&DaughterCuts::dcaRelToOrigin, "dcaRelToOrigin", "DCA rel. to origin [cm]", YAML::Flow),
        yaml::Property(&DaughterCuts::beta, "beta", "Speed [c]", YAML::Flow));
    };

    struct ParticleCuts {
      DaughterCuts daughterA;        
      DaughterCuts daughterB;        
      float maxDcaRelToPrimVertex;   
      float maxDcaBetweenDaughters;  
      Range_t<float> decayLength;    
      Range_t<float> daughterVtxZ;   
      float minOpeningAngle;         
      Range_t<float> chi2NdfTopo;    
      Range_t<float> chi2NdfGeo;     
 
      CBM_YAML_PROPERTIES(
        yaml::Property(&ParticleCuts::daughterA, "daughterA", "Individual cuts for daughter \"a\""),
        yaml::Property(&ParticleCuts::daughterB, "daughterB", "Individual cuts for daughter \"b\""),
        yaml::Property(&ParticleCuts::maxDcaRelToPrimVertex, "maxDcaRelToPrimVertex", "Max. DCA relative to primary vertex [cm]"),
        yaml::Property(&ParticleCuts::maxDcaBetweenDaughters, "maxDcaBetweenDaughters", "Max. DCA between two daughters [cm]"),
        yaml::Property(&ParticleCuts::decayLength, "decayLength", "Decay length of particle (afterburner?) [cm]", YAML::Flow),
        yaml::Property(&ParticleCuts::daughterVtxZ, "daughterVtxZ", "z-coordinate of daughter vertex [cm]", YAML::Flow),
        yaml::Property(&ParticleCuts::minOpeningAngle, "minOpeningAngle", "Min. opening angle between daughters [radians]"),
        yaml::Property(&ParticleCuts::chi2NdfTopo, "chi2NdfTopo", "Topology chi2/NDF (with reconstructed PV)", YAML::Flow),
        yaml::Property(&ParticleCuts::chi2NdfGeo, "chi2NdfGeo", "chi2/NDF (with respect to origin)", YAML::Flow));
    };

    struct CutValues {
      TrackCuts trackCuts;          
      KfpFinderCuts kfpFinderCuts;  
      ParticleCuts particleCuts;    
      CBM_YAML_PROPERTIES(
        yaml::Property(&CutValues::trackCuts, "trackCuts", "Cuts on tracks at pre-selection stage"),
        yaml::Property(&CutValues::kfpFinderCuts, "kfpFinderCuts", "Internal KFParticleFinder cuts"),
        yaml::Property(&CutValues::particleCuts, "particleCuts", "Cuts on the final V0 candidates selection")
      );

      void Init();
    };
 
    //* Different structures to store intermediate track/particle properties for performing the selection

    struct TrackProperty {
      double dcaRelToOrigin;  
      double beta;            
      ETrackPid pid;          
    };

    struct DaughterProperty {
      double dcaRelToOrigin;  
      double beta;            
    };

    struct ParticleProperty {
      DaughterProperty daughterA;  
      DaughterProperty daughterB;  
      double dcaRelToPrimVertex;   
      double daughterVtxZ;         
      double dcaBetweenDaughters;  
      double decayLength;          
      double openingAngle;         
      double chi2NdfTopo;          
      double chi2NdfGeo;           
    };
 
    //* Class public methods

    V0FinderCutter() = default;

    V0FinderCutter(const std::string& filename);

    V0FinderCutter(const V0FinderCutter&) = default;

    V0FinderCutter(V0FinderCutter&&) = default;

    ~V0FinderCutter() = default;

    V0FinderCutter& operator=(const V0FinderCutter&) = default;

    V0FinderCutter& operator=(V0FinderCutter&&) = default;

    void ApplyCutsToKFParticleFinder(KFParticleFinder* pFinder) const;

    void ReadCutsFromYaml(const std::string& filename);

    bool SelectParticle(const ParticleProperty& particleProperty) const;

    bool SelectTrack(const TrackProperty& trackProperty) const;

    void SetCuts(const CutValues& cuts);

    std::string ToString() const;

    static constexpr int GetV0Pdg()
    {
      if constexpr (EV0Type::Lambda == V0Type) {
        return 3122;  // Lambda
      }
      else {
        return -2;  // undef
      }
    }
 
   private:
    CutValues fCuts;         
    std::string fsName{""};  
  };
}  // namespace cbm::algo::kfp
 
#endif  // KfpV0FinderCutter_h