CMS_2011_S8973270.cc

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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableFinalState.hh"
#include "Rivet/Projections/FastJets.hh"

namespace Rivet {


  class CMS_2011_S8973270 : public Analysis {
  public:

    /// Constructor
    CMS_2011_S8973270() : Analysis("CMS_2011_S8973270") {  }


    void init() {
      FinalState fs;
      FastJets jetproj(fs, FastJets::ANTIKT, 0.5);
      jetproj.useInvisibles();
      addProjection(jetproj, "Jets");

      UnstableFinalState ufs;
      addProjection(ufs, "UFS");

      // Book histograms
      _h_dsigma_dR_56GeV = bookHisto1D(1,1,1);
      _h_dsigma_dR_84GeV = bookHisto1D(2,1,1);
      _h_dsigma_dR_120GeV = bookHisto1D(3,1,1);
      _h_dsigma_dPhi_56GeV = bookHisto1D(4,1,1);
      _h_dsigma_dPhi_84GeV = bookHisto1D(5,1,1);
      _h_dsigma_dPhi_120GeV = bookHisto1D(6,1,1);

      _countMCDR56 = 0;
      _countMCDR84 = 0;
      _countMCDR120 = 0;
      _countMCDPhi56 = 0;
      _countMCDPhi84 = 0;
      _countMCDPhi120 = 0;
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const double weight = event.weight();

      const Jets& jets = applyProjection<FastJets>(event,"Jets").jetsByPt();
      const UnstableFinalState& ufs = applyProjection<UnstableFinalState>(event, "UFS");

      // Find the leading jet pT and eta
      if (jets.size() == 0) vetoEvent;
      const double ljpT = jets[0].pT();
      const double ljeta = jets[0].eta();
      MSG_DEBUG("Leading jet pT / eta: " << ljpT << " / " << ljeta);

      // Minimum requirement for event
      if (ljpT > 56*GeV && fabs(ljeta) < 3.0) {
        // Find B hadrons in event
        int nab = 0, nb = 0; //counters for all B and independent B hadrons
        double etaB1 = 7.7, etaB2 = 7.7;
        double phiB1 = 7.7, phiB2 = 7.7;
        double pTB1 = 7.7, pTB2 = 7.7;

        foreach (const Particle& p, ufs.particles()) {
          int aid = p.abspid();
          if (aid/100 == 5 || aid/1000==5) {
            nab++;
            // 2J+1 == 1 (mesons) or 2 (baryons)
            if (aid%10 == 1 || aid%10 == 2) {
              // No B decaying to B
              if (aid != 5222 && aid != 5112 && aid != 5212 && aid != 5322) {
                if (nb==0) {
                  etaB1 = p.eta();
                  phiB1 = p.phi();
                  pTB1 = p.pT();
                } else if (nb==1) {
                  etaB2 = p.eta();
                  phiB2 = p.phi();
                  pTB2 = p.pT();
                }
                nb++;
              }
            }
            MSG_DEBUG("ID " << aid <<  " B hadron");
          }
        }

        if (nb==2 && pTB1 > 15*GeV && pTB2 > 15*GeV && fabs(etaB1) < 2.0 && fabs(etaB2) < 2.0) {
          double dPhi = deltaPhi(phiB1, phiB2);
          double dR = deltaR(etaB1, phiB1, etaB2, phiB2);
          MSG_DEBUG("DR/DPhi " << dR << " " << dPhi);

          // MC counters
          if (dR > 2.4) _countMCDR56 += weight;
          if (dR > 2.4 && ljpT > 84*GeV) _countMCDR84 += weight;
          if (dR > 2.4 && ljpT > 120*GeV) _countMCDR120 += weight;
          if (dPhi > 3.*PI/4.) _countMCDPhi56 += weight;
          if (dPhi > 3.*PI/4. && ljpT > 84*GeV) _countMCDPhi84 += weight;
          if (dPhi > 3.*PI/4. && ljpT > 120*GeV) _countMCDPhi120 += weight;

          _h_dsigma_dR_56GeV->fill(dR, weight);
          if (ljpT > 84*GeV) _h_dsigma_dR_84GeV->fill(dR, weight);
          if (ljpT > 120*GeV) _h_dsigma_dR_120GeV->fill(dR, weight);
          _h_dsigma_dPhi_56GeV->fill(dPhi, weight);
          if (ljpT > 84*GeV) _h_dsigma_dPhi_84GeV->fill(dPhi, weight);
          if (ljpT > 120*GeV) _h_dsigma_dPhi_120GeV->fill(dPhi, weight);
          //MSG_DEBUG("nb " << nb << " " << nab);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      MSG_DEBUG("crossSection " << crossSection() << " sumOfWeights " << sumOfWeights());

      // Hardcoded bin widths
      double DRbin = 0.4;
      double DPhibin = PI/8.0;
      // Find out the correct numbers
      double nDataDR56 = 25862.20;
      double nDataDR84 = 5675.55;
      double nDataDR120 = 1042.72;
      double nDataDPhi56 = 24220.00;
      double nDataDPhi84 = 4964.00;
      double nDataDPhi120 = 919.10;
      double normDR56 = (_countMCDR56 > 0.) ? nDataDR56/_countMCDR56 : crossSection()/sumOfWeights();
      double normDR84 = (_countMCDR84 > 0.) ? nDataDR84/_countMCDR84 : crossSection()/sumOfWeights();
      double normDR120 = (_countMCDR120 > 0.) ? nDataDR120/_countMCDR120 : crossSection()/sumOfWeights();
      double normDPhi56 = (_countMCDPhi56 > 0.) ? nDataDPhi56/_countMCDPhi56 : crossSection()/sumOfWeights();
      double normDPhi84 = (_countMCDPhi84 > 0.) ? nDataDPhi84/_countMCDPhi84 : crossSection()/sumOfWeights();
      double normDPhi120 = (_countMCDPhi120 > 0.) ? nDataDPhi120/_countMCDPhi120 : crossSection()/sumOfWeights();
      scale(_h_dsigma_dR_56GeV, normDR56*DRbin);
      scale(_h_dsigma_dR_84GeV, normDR84*DRbin);
      scale(_h_dsigma_dR_120GeV, normDR120*DRbin);
      scale(_h_dsigma_dPhi_56GeV, normDPhi56*DPhibin);
      scale(_h_dsigma_dPhi_84GeV, normDPhi84*DPhibin);
      scale(_h_dsigma_dPhi_120GeV, normDPhi120*DPhibin);
    }

    //@}


  private:

    /// @name Counters
    //@{
    double _countMCDR56, _countMCDR84, _countMCDR120;
    double _countMCDPhi56, _countMCDPhi84, _countMCDPhi120;
    //@}

    /// @name Histograms
    //@{
    Histo1DPtr _h_dsigma_dR_56GeV, _h_dsigma_dR_84GeV, _h_dsigma_dR_120GeV;
    Histo1DPtr _h_dsigma_dPhi_56GeV, _h_dsigma_dPhi_84GeV, _h_dsigma_dPhi_120GeV;
    //@}

  };


  // Hook for the plugin system
  DECLARE_RIVET_PLUGIN(CMS_2011_S8973270);

}