Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/Hemispheres.hh"
#include "Rivet/Projections/ParisiTensor.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Projections/Thrust.hh"
#include "fastjet/EECambridgePlugin.hh"

namespace Rivet {


  /// @brief event shapes vs thrust direction
  class DELPHI_2000_I522656 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_2000_I522656);


    /// @name Analysis methods
    ///@{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections.
      declare(Beam(), "Beams");
      const FinalState fs;
      declare(fs, "FS");
      const Thrust thrust(fs);
      declare(thrust, "Thrust");
      declare(Sphericity(fs), "Sphericity");
      declare(ParisiTensor(fs), "Parisi");
      declare(Hemispheres(thrust), "Hemispheres");
      declare(FastJets(fs, JetAlg::DURHAM, 0.7), "DurhamJets");
      declare(FastJets(fs, JetAlg::JADE), "JadeJets");

      // book histograms
      vector<double> bins = {0.00, 0.12, 0.24, 0.36, 0.48, 0.60, 0.72, 0.84, 0.96};
      book(_h_EEC, bins);
      book(_h_AEEC, bins);
      book(_h_cone, bins);
      book(_h_thrust, {0.12, 0.24, 0.36});
      // thrust angle binned
      size_t iy = 1, ioff = 0;
      for (size_t ix = 0; ix < _h_EEC->numBins(); ++ix) {
        book(_h_EEC->bin(ix + 1), 21 + ioff, 1, iy);
        book(_h_AEEC->bin(ix + 1), 25 + ioff, 1, iy);
        book(_h_cone->bin(ix + 1), 29 + ioff, 1, iy);
        if (ioff == 0) {
          book(_h_thrust->bin(iy), 33, 1, iy);
        }
        ++iy;
        if (iy == 3) {
          ++ioff;
          iy = 1;
        }
      }
      // total values
      book(_h_EEC_all, 3, 1, 1);
      book(_h_AEEC_all, 4, 1, 1);
      book(_h_cone_all, 5, 1, 1);
      book(_h_thrust_all, 6, 1, 1);
      book(_h_Oblateness, 7, 1, 1);
      book(_h_C, 8, 1, 1);
      book(_h_heavy, 9, 1, 1);
      book(_h_sum, 10, 1, 1);
      book(_h_diff, 11, 1, 1);
      book(_h_wide, 12, 1, 1);
      book(_h_total, 13, 1, 1);
      book(_h_jade, 17, 1, 1);
      book(_h_dur, 18, 1, 1);
      book(_h_cam, 20, 1, 1);
      book(_h_bin, "/TMP/hbin", bins);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");
      if (fs.particles().size() < 2) vetoEvent;
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      // thrust
      const Thrust& thrust = apply<Thrust>(event, "Thrust");
      // angle bettwen thrust and beam
      double cosThrust = abs(beams.first.p3().unit().dot(thrust.thrustAxis()));
      _h_bin->fill(cosThrust);
      // thrust and related
      _h_thrust_all->fill(1. - thrust.thrust());
      _h_thrust->fill(cosThrust, 1. - thrust.thrust());
      _h_Oblateness->fill(thrust.oblateness());

      // visible energy and make pseudojets
      double Evis = 0.0;
      PseudoJets pjs;
      for (const Particle& p : fs.particles()) {
        Evis += p.E();
        fastjet::PseudoJet pj = p;
        pjs.push_back(pj);
      }
      double Evis2 = sqr(Evis);
      // (A)EEC
      // Need iterators since second loop starts at current outer loop iterator, i.e. no "foreach" here!
      for (Particles::const_iterator p_i = fs.particles().begin(); p_i != fs.particles().end(); ++p_i) {
        for (Particles::const_iterator p_j = p_i; p_j != fs.particles().end(); ++p_j) {
          if (p_i == p_j) continue;
          const Vector3 mom3_i = p_i->momentum().p3();
          const Vector3 mom3_j = p_j->momentum().p3();
          const double energy_i = p_i->momentum().E();
          const double energy_j = p_j->momentum().E();
          const double thetaij = 180. * mom3_i.unit().angle(mom3_j.unit()) / M_PI;
          double eec = (energy_i * energy_j) / Evis2;
          eec *= 2.;
          _h_EEC_all->fill(thetaij, eec);
          _h_EEC->fill(cosThrust, thetaij, eec);
          if (thetaij < 90.) {
            _h_AEEC_all->fill(thetaij, -eec);
            _h_AEEC->fill(cosThrust, thetaij, -eec);
          }
          else {
            _h_AEEC_all->fill(180. - thetaij, eec);
            _h_AEEC->fill(cosThrust, 180. - thetaij, eec);
          }
        }
      }
      // hemisphere related
      const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");
      _h_heavy->fill(hemi.scaledM2high());
      _h_diff->fill(hemi.scaledM2diff());
      _h_sum->fill(hemi.scaledM2low() + hemi.scaledM2high());
      _h_wide->fill(hemi.Bmax());
      _h_total->fill(hemi.Bsum());
      // C-parameter
      const ParisiTensor& parisi = apply<ParisiTensor>(event, "Parisi");
      _h_C->fill(parisi.C());
      // jets
      const FastJets& durjet = apply<FastJets>(event, "DurhamJets");
      const FastJets& jadejet = apply<FastJets>(event, "JadeJets");
      if (durjet.clusterSeq()) _h_dur->fill(durjet.clusterSeq()->exclusive_ymerge_max(2));
      if (jadejet.clusterSeq()) _h_jade->fill(jadejet.clusterSeq()->exclusive_ymerge_max(2));
      // Cambridge is more complicated, inclusive defn
      for (size_t i = 0; i < _h_cam->numBins(); ++i) {
        double ycut = _h_cam->bin(i).xMax();
        // double width = _h_y_2_Cambridge->bin(i).xWidth();
        fastjet::EECambridgePlugin plugin(ycut);
        fastjet::JetDefinition jdef(&plugin);
        fastjet::ClusterSequence cseq(pjs, jdef);
        unsigned int njet = cseq.inclusive_jets().size();
        if (njet == 2) {
          _h_cam->fill(_h_cam->bin(i).xMid());
          break;
        }
      }
      // jet cone
      Vector3 jetAxis = thrust.thrustAxis();
      if (hemi.highMassDirection()) jetAxis *= -1.;
      for (const Particle& p : fs.particles()) {
        const double thetaij = 180. * jetAxis.angle(p.p3().unit()) / M_PI;
        double jcef = p.E() / Evis;
        _h_cone_all->fill(thetaij, jcef);
        _h_cone->fill(cosThrust, thetaij, jcef);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (size_t ix = 0; ix < _h_EEC->numBins(); ++ix) {
        if (ix < 2) scale(_h_thrust->bin(ix + 1), 1. / _h_bin->bin(ix + 1).sumW());
        scale(_h_EEC->bin(ix + 1), 180. / M_PI / _h_bin->bin(ix + 1).sumW());
        scale(_h_AEEC->bin(ix + 1), 180. / M_PI / _h_bin->bin(ix + 1).sumW());
        scale(_h_cone->bin(ix + 1), 180. / M_PI / _h_bin->bin(ix + 1).sumW());
      }

      scale(_h_thrust_all, 1. / sumOfWeights());
      scale(_h_EEC_all, 180. / M_PI / sumOfWeights());
      scale(_h_AEEC_all, 180. / M_PI / sumOfWeights());
      scale(_h_cone_all, 180. / M_PI / sumOfWeights());
      scale(_h_Oblateness, 1. / sumOfWeights());
      scale(_h_C, 1. / sumOfWeights());
      scale(_h_heavy, 1. / sumOfWeights());
      scale(_h_sum, 1. / sumOfWeights());
      scale(_h_diff, 1. / sumOfWeights());
      scale(_h_wide, 1. / sumOfWeights());
      scale(_h_total, 1. / sumOfWeights());
      scale(_h_dur, 1. / sumOfWeights());
      scale(_h_jade, 1. / sumOfWeights());
      scale(_h_cam, 1. / sumOfWeights());
    }

    ///@}


    /// @name Histograms
    ///@{
    Histo1DPtr _h_thrust_all, _h_EEC_all, _h_AEEC_all, _h_cone_all;
    Histo1DPtr _h_Oblateness, _h_C, _h_heavy, _h_sum, _h_diff, _h_wide, _h_total;
    Histo1DPtr _h_jade, _h_dur, _h_cam;
    Histo1DGroupPtr _h_thrust, _h_EEC, _h_AEEC, _h_cone;
    Histo1DPtr _h_bin;
    ///@}
  };


  RIVET_DECLARE_PLUGIN(DELPHI_2000_I522656);

}