WZVetoedShower.cxx

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/*
  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
*/
 
#include "UserHooksUtils.h"
#include "Pythia8_i/UserHooksFactory.h"
#include <stdexcept>
#include <iostream>
 
namespace Pythia8{
  class WZVetoedShower;
}
 
Pythia8_UserHooks::UserHooksFactory::Creator<Pythia8::WZVetoedShower> wzVetoedShowerCreator("WZVetoedShower");
 
namespace Pythia8{

 
  class WZVetoedShower : public UserHooks{
 
  public:
 
    WZVetoedShower(): m_powhegScale(0.){
 
      std::cout<<"*******************************************************************"<<std::endl;
      std::cout<<"*                                                                 *"<<std::endl;
      std::cout<<"* Using vetoed shower for PoWHEG colourless resonance production! *"<<std::endl;
      std::cout<<"*                                                                 *"<<std::endl;
      std::cout<<"*******************************************************************"<<std::endl;
      
    }
 
    ~WZVetoedShower(){}

    bool doVetoMPIStep(int nMPI, const Event &){
 
      // Only do anything on the first call.
      if(nMPI > 1) return false;
      
      m_powhegScale = infoPtr->QRen();
//      m_powhegScale = infoPtr->QFac();
 
//      std::cout<<" ******** veto scale = "<<m_powhegScale<<", "<<infoPtr->QRen() <<" *********"<<std::endl;  
      
      return false;
    }

    bool doVetoISREmission(int, const Event &evt, int iSys){
 
      // only veto emissions from the hard system
      if(iSys != 0) return false;
      
      size_t emission = Pythia8_UserHooks::findLastISREmission(evt);
 
      // Veto emission above the veto scale
      if(evt[emission].pT() > m_powhegScale) return true;
 
      return false;
    }

    bool doVetoFSREmission(int, const Event &evt, int iSys, bool){
 
      // only veto emissions from the hard system
      if(iSys != 0) return false;
      
      size_t emission = Pythia8_UserHooks::findLastFSREmission(evt);
 
      // Veto if above the POWHEG scale
      if (evt[emission].pT() > m_powhegScale) return true;
 
      return false;
    }

    bool canVetoMPIStep(){return true;}
    int numberVetoMPIStep(){return 1;}
    bool canVetoISREmission(){return true;}
    bool canVetoFSREmission(){return true;}
 
  private:
 
    double m_powhegScale;
  };
}