CompactHardTruth.h

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
 
// CompactHardTruth.h
// Header file for class CompactHardTruth
// Author: Frank Paige <paige@bnl.gov>
//
// Algorithm to construct small, consistent hard-scattering HepMC truth
// record from GEN_EVENT. Only final partons have physical momenta, so
// must recluster them. Main steps:
// (1)  Identify hadronization vertices with partons in, hadrons out.
// (2)  Detach their incoming partons and delete their descendants.
// (3)  Iteratively recombine 1->2 branchings of final partons with
//      mass M < Mcut. Split 2->1 nonperturbative color recombinations.
// (4)  Remove partons not connected to hard process. May make apparent
//      anomalies, e.g., dropping soft q from incoming g -> g q.
//
// New final partons have correct momenta and ancestors/descendants.
// CompactHardTruth changes particles/vertices, so it cannot be used directly 
// with thinning, but it can be used in parallel.
//
#ifndef DERIVATIONFRAMEWORK_COMPACTHARDTRUTH_H
#define DERIVATIONFRAMEWORK_COMPACTHARDTRUTH_H 1
 
// STL includes
#include <string>
 
// FrameWork includes
#include "AthenaBaseComps/AthAlgorithm.h"
#include "AtlasHepMC/GenVertex_fwd.h" //HepMC::ConstGenVertexPtr
#include "AtlasHepMC/SimpleVector.h" //HepMC::FourVector typedef
 
 
namespace DerivationFramework {
 
class CompactHardTruth
  : public ::AthAlgorithm
{ 

  // Public methods: 
 public: 

  CompactHardTruth( const std::string& name, ISvcLocator* pSvcLocator );

  virtual ~CompactHardTruth(); 
 
  // Athena algorithm Hooks
  virtual StatusCode  initialize();
  virtual StatusCode  execute(const EventContext& ctx);
  virtual StatusCode  finalize();
 
  // Total in/out FourVector for vertex
  virtual HepMC::FourVector vtxInMom(HepMC::ConstGenVertexPtr);
  virtual HepMC::FourVector vtxOutMom(HepMC::ConstGenVertexPtr);
 
 private: 

  CompactHardTruth();

  std::string m_mcEventsName;
  std::string m_thinnedMcEventsName;
 
  // Variables
  int m_evtCount = 0;
  int m_missCount = 0;
  float m_partonCut{};
  float m_hardCut{};
 
  int m_dangleFound = 0;
  int m_dangleRemoved = 0;
  float m_danglePtMax = 0.0F;
  float m_danglePtCut{};
 
  int m_maxCount{};
 
  int m_thinParticles = 0;
  int m_thinVertices = 0;
 
}; 
 
 
} //> end namespace DerivationFramework
#endif //> !DERIVATIONFRAMEWORK_COMPACTHARDTRUTH_H