ATLAS_2011_I928289_Z.cc

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// -*- C++ -*-
#include <cmath>

#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ZFinder.hh"


namespace Rivet {

  using namespace Cuts;

  class ATLAS_2011_I928289_Z : public Analysis {
  public:

    /// Constructor
    ATLAS_2011_I928289_Z()
      : Analysis("ATLAS_2011_I928289_Z")
    {
      setNeedsCrossSection(true);
    }


  public:

    /// @name Analysis methods
    //@{
    
    /// Book histograms and initialise projections before the run
    void init() {

      FinalState fs;
      
      Cut cut =  pT >= 20.0*GeV;

      ZFinder zfinder_ee_bare(   fs, cut, PID::ELECTRON, 66.0*GeV, 116.0*GeV, 0.0, ZFinder::CLUSTERNODECAY, ZFinder::NOTRACK);
      ZFinder zfinder_ee_dressed(fs, cut, PID::ELECTRON, 66.0*GeV, 116.0*GeV, 0.1, ZFinder::CLUSTERNODECAY, ZFinder::NOTRACK);
      ZFinder zfinder_mm_bare(   fs, cut, PID::MUON    , 66.0*GeV, 116.0*GeV, 0.0, ZFinder::CLUSTERNODECAY, ZFinder::NOTRACK);
      ZFinder zfinder_mm_dressed(fs, cut, PID::MUON    , 66.0*GeV, 116.0*GeV, 0.1, ZFinder::CLUSTERNODECAY, ZFinder::NOTRACK);

      addProjection(zfinder_ee_bare   , "ZFinder_ee_bare"   );
      addProjection(zfinder_ee_dressed, "ZFinder_ee_dressed");
      addProjection(zfinder_mm_bare   , "ZFinder_mm_bare"   );
      addProjection(zfinder_mm_dressed, "ZFinder_mm_dressed");

      //y(Z) cross-section dependence 
      _h_Z_y_ee_bare     = bookHisto1D(1, 1, 1);
      _h_Z_y_ee_dressed  = bookHisto1D(1, 1, 2);
      _h_Z_y_mm_bare     = bookHisto1D(1, 1, 3);
      _h_Z_y_mm_dressed  = bookHisto1D(1, 1, 4);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      const double weight = event.weight();

      ///Do the event by event analysis here
      const ZFinder& zfinder_ee_bare     = applyProjection<ZFinder>(event, "ZFinder_ee_bare"   );
      const ZFinder& zfinder_ee_dressed  = applyProjection<ZFinder>(event, "ZFinder_ee_dressed");
      const ZFinder& zfinder_mm_bare     = applyProjection<ZFinder>(event, "ZFinder_mm_bare"   );
      const ZFinder& zfinder_mm_dressed  = applyProjection<ZFinder>(event, "ZFinder_mm_dressed");

      FillPlots1d(zfinder_ee_bare   , _h_Z_y_ee_bare   , weight);
      FillPlots1d(zfinder_ee_dressed, _h_Z_y_ee_dressed, weight);
      FillPlots1d(zfinder_mm_bare   , _h_Z_y_mm_bare   , weight);
      FillPlots1d(zfinder_mm_dressed, _h_Z_y_mm_dressed, weight);

    }

    
    void FillPlots1d(const ZFinder& zfinder, Histo1DPtr hist, double weight) {

      if (zfinder.bosons().size() != 1) return;
      
      const FourMomentum zmom = zfinder.bosons()[0].momentum();
      
      hist->fill( fabs(zmom.rapidity()), weight);

      return; 
    } 

    /// Normalise histograms etc., after the run
    void finalize() {

      /// Print summary info
      const double xs_pb(crossSection() / picobarn);
      const double sumw(sumOfWeights());
      MSG_INFO("Cross-Section/pb: " << xs_pb      );
      MSG_INFO("Sum of weights  : " << sumw       );
      MSG_INFO("nEvents         : " << numEvents());

      const double sf(0.5 * xs_pb / sumw); // 0.5 accounts for rapidity bin width

      ///Normalise, scale and otherwise manipulate histograms here
      scale(_h_Z_y_ee_bare   , sf); 
      scale(_h_Z_y_ee_dressed, sf); 
      scale(_h_Z_y_mm_bare   , sf); 
      scale(_h_Z_y_mm_dressed, sf); 

    }

    //@}


  private:

    // Data members like post-cuts event weight counters go here


  private:

    /// @name Histograms
    //@{
    Histo1DPtr _h_Z_y_ee_bare;
    Histo1DPtr _h_Z_y_ee_dressed;
    Histo1DPtr _h_Z_y_mm_bare;
    Histo1DPtr _h_Z_y_mm_dressed;
    //@}
  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(ATLAS_2011_I928289_Z);

}